Cyclopolymerizable compounds for 3d printing

ABSTRACT

In one aspect, inks for use with a three-dimensional (3D) printing system are described herein. In some embodiments, an ink described herein comprises 10-70 wt. % cyclopolymerizable monomer, based on the total weight of the ink. The cyclopolymerizable monomer comprises a first ethenyl or ethynyl moiety and a second ethenyl or ethynyl moiety. Additionally, the α-carbon of the first ethenyl or ethynyl moiety and the α-carbon of the second ethenyl or ethynyl moiety have a 1,5-, 1,6-, 1,7-, or 1,8-relationship.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 16/152,787, filed Oct. 5, 2018 which claims priority pursuantto 35 U.S.C. § 119 to U.S. Provisional Patent Application No.62/568,619, filed Oct. 5, 2017, which are hereby incorporated byreference in their entirety.

FIELD

The present invention relates to cyclopolymerizable compounds and, inparticular, inks comprising such compounds for use withthree-dimensional (3D) printing systems.

BACKGROUND

Some commercially available 3D printers, such as the ProJet™ 3D Printersmanufactured by 3D Systems of Rock Hill, S.C., use inks, which are alsoknown as build materials, that are jetted through a print head as aliquid to form various 3D objects, articles, or parts. Other 3D printingsystems also use an ink that is jetted through a print head or otherwisedispensed onto a substrate. In some instances, the ink is solid atambient temperatures and converts to liquid at elevated jettingtemperatures. In other instances, the ink is liquid at ambienttemperatures. Moreover, in some cases, the ink can be cured followingdispensing and/or deposition of the ink onto the substrate.

Other 3D printers form 3D articles from a reservoir, vat, or containerof a fluid ink or build material or a powdered ink or build material. Insome cases, a binder material or a laser or other source of energy isused to selectively solidify or consolidate layers of the ink or buildmaterial in a stepwise fashion to provide the 3D article.

Inks for 3D printing systems can be used to form a variety of articlesfor a variety of applications, including in a manner describedhereinabove. However, there is a very high demand for inks that can formarticles having superior mechanical properties. For example, there is ahigh demand for inks that can form articles with mechanical propertiessimilar to articles formed from thermoplastic materials.

Prior inks for 3D printing systems that contain acrylates can be used toprint articles with very good resolution, but often the resultingarticles are rigid, brittle, or flexible but easily breakable. Theimpact resistance of such articles can be especially low compared tosome other articles. Therefore, there exists a need for improvedacrylate-containing inks for 3D printing that form articles havingimproved mechanical properties. Particularly, a need exists foracrylate-containing inks that produce articles having mechanicalproperties more like those exhibited by articles formed fromthermoplastic materials.

SUMMARY

In one aspect, inks for use with a 3D printer are described herein,which in some embodiments, may offer one or more advantages over prioracrylate-containing inks. For example, inks described herein can be usedto print articles with improved mechanical properties, includingimproved impact resistance, compared to those printed with prioracrylate-containing inks. In some embodiments, articles printed usinginks described herein also have improved tensile modulus, tensilestrength, and/or elongation, compared to articles printed using prioracrylate-containing inks. In some cases, articles printed using inksdescribed herein have a combination of both high elongation and alsohigh impact strength, when compared to other compositions. Additionally,in some cases, inks described herein have reduced viscosity compared toprior acrylate-containing inks. As a result, inks described herein canbe used in a variety of different 3D printers, such as those based onStereolithography (SLA), Digital Light Processing (DLP), and Multi-JetPrinting (MJP). Further, due at least in part to their reducedviscosity, inks described herein can also print easily and quickly.

In some embodiments, an ink for use in a 3D printing system describedherein comprises 10-70 wt. % cyclopolymerizable monomer, based on thetotal weight of the ink. The cyclopolymerizable monomer comprises afirst ethenyl or ethynyl moiety and a second ethenyl or ethynyl moiety.Additionally, the α-carbon of the first ethenyl or ethynyl moiety andthe α-carbon of the second ethenyl or ethynyl moiety have a 1,5-, 1,6-,1,7-, or 1,8-relationship. In some cases, the cyclopolymerizable monomerhas the specific structure of Formula (I):

wherein:R₁ is a hydrocarbon group having 1-4 carbon atoms;R₂ is a hydrocarbon group having 1-4 carbon atoms;the total number of carbon atoms of R₁ and R₂ does not exceed 5;R₃ is HC═CH₂ or C≡CH;R₄ is HC═CH₂ or C≡CH;

R₅ is

or a polymerizable moiety; andR₆ is a substituted or unsubstituted hydrocarbon group having 1-30carbon atoms. The polymerizable moiety, in some instances, comprises a(meth)acrylate moiety.

In other embodiments, the cyclopolymerizable monomer has the structureof Formula (II):

wherein:R₁ is a hydrocarbon group having 1-4 carbon atoms;R₂ is a hydrocarbon group having 1-4 carbon atoms;the total number of carbon atoms of R₁ and R₂ does not exceed 5;R₃ is HC═CH₂ or C≡CH;R₄ is HC═CH₂ or C≡CH;R₅ is a hydrocarbon group having 1-30 carbon atoms or a poly(alkyleneglycol) having 2-30 alkylene glycol repeating units;R₇ is a hydrocarbon group having 1-4 carbon atoms;R₈ is a hydrocarbon group having 1-4 carbon atoms;the total number of carbon atoms of R₇ and R₈ does not exceed 5;R₉ is HC═CH₂ or C≡CH;R₁₀ is HC═CH₂ or C≡CH;

In addition to the above-described cyclopolymerizable monomer, an inkdescribed herein, in some cases, may further comprise 10-60 wt. % ofoligomeric curable material and/or up to 80 wt. % of additionalmonomeric curable material, based on the total weight of the ink. An inkdescribed herein may also comprise at least one photoinitiator, at leastone colorant, or both. Additionally, an ink described herein maycomprise one or more additives selected from the group consisting ofinhibitors and stabilizing agents.

Moreover, an ink described herein, in some instances, has a viscosity of1600 centipoise (cP) or less at 30° C., or of 500 cP or less at 30° C.

In another aspect, methods of printing a 3D article using any of theforegoing inks are described herein. In some cases, for instance, such amethod comprises selectively depositing layers of an ink in a fluidstate onto a substrate. Moreover, in some embodiments, the ink ispartially cured prior to completion of deposition of all layers of theink. Partially curing, in some embodiments, primarily comprisespolymerizing the first ethenyl or ethynyl moiety, the second ethenyl orethynyl moiety, and/or a (meth)acrylate moiety of the cyclopolymerizablemonomer via alkene, alkyne, and/or (meth)acrylate polymerization. Inother instances, partially curing the ink primarily comprisescyclopolymerizing the cyclopolymerizable monomer of the ink.

Additionally, in some cases, following the completion of deposition ofall layers of the ink, the ink is post-cured. Post-curing, in someembodiments, primarily comprises polymerizing the first ethenyl orethynyl moiety, the second ethenyl or ethynyl moiety, and/or a(meth)acrylate moiety of the cyclopolymerizable monomer via alkene,alkyne, and/or (meth)acrylate polymerization. Alternatively, post-curingthe ink primarily comprises cyclopolymerizing the cyclopolymerizablemonomer.

Further, in some cases, partially curing and post-curing each comprisephotocuring, i.e., curing with a light source. Moreover, in someembodiments, a light source used for post-curing has a higher energythan a light source use for partially curing. For example, in somecases, the light source used for post-curing may be a Hg lamp and thelight source used for partially curing may be a Xe arc lamp.

In another method of printing a 3D article described herein, the methodcomprises retaining an ink described herein in a fluid state in acontainer; and selectively applying energy to the ink in the containerto solidify at least a portion of a first fluid layer of the ink,thereby forming a first solidified layer that defines a firstcross-section of the article. Such a method can further comprise raisingor lowering the first solidified layer to provide a second fluid layerof the ink at a surface of the fluid ink in the container; andselectively applying energy to the ink in the container to solidify atleast a portion of the second fluid layer of the ink, thereby forming asecond solidified layer that defines a second cross-section of thearticle, the first cross-section and the second cross-section beingbonded to one another in a z-direction. As described furtherhereinbelow, the foregoing steps may be repeated any desired number oftimes needed to complete the 3D article.

Moreover, in some cases, selectively applying energy to the ink in thecontainer comprises partially curing the ink. Partially curing the inkmay primarily comprise polymerizing the first ethenyl or ethynyl moiety,the second ethenyl or ethynyl moiety, and/or a (meth)acrylate moiety ofthe cyclopolymerizable monomer via alkene, alkyne, and/or (meth)acrylatepolymerization. In other embodiments, partially curing the ink primarilycomprises cyclopolymerizing the cyclopolymerizable monomer.

In addition, in some instances, a method described further comprisespost-curing the 3D article following its formation. Post-curing the ink,in some cases, primarily comprises polymerizing the first ethenyl orethynyl moiety, the second ethenyl or ethynyl moiety, and/or a(meth)acrylate moiety (if present) of the cyclopolymerizable monomer viaalkene, alkyne, and/or (meth)acrylate polymerization. Alternatively, insome cases, post-curing the ink primarily comprises cyclopolymerizingthe cyclopolymerizable monomer of the ink. Further, partially curing andpost curing each may comprise photocuring. In some such instances, alight source used for post-curing may have a higher energy than a lightsource used for partially curing. For example, a Hg lamp may be used forpost-curing, and a Xe arc lamp may be used for partially curing.

In still another aspect, printed 3D articles are described herein. Inparticular, 3D articles formed from an ink and/or using a methoddescribed hereinabove are disclosed. Such printed 3D articles, in somecases, have superior mechanical properties or other properties comparedto some other 3D articles.

In yet another aspect, cyclopolymerizable compounds are describedherein. Such compounds can be used in inks, methods, and articlesdescribed hereinabove, or in other applications that are not necessarilylimited to 3D printing. In some embodiments, a compound described hereinhas the structure of Formula (I) or Formula (II) hereinabove. Forexample, in some cases, a novel compound described herein is

These and other embodiments are described in greater detail in thedetailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates cyclopolymerization of a cyclopolymerizable compoundor monomer according to some embodiments described herein.

FIG. 2 illustrates (meth)acrylate polymerization of a cyclopolymerizablecompound or monomer according to some embodiments described herein.

FIG. 3 illustrates a synthetic scheme for making a cyclopolymerizablecompound or monomer according to one embodiment described herein.

DETAILED DESCRIPTION

Embodiments described herein can be understood more readily by referenceto the following detailed description, figures, and examples. Elements,apparatus and methods described herein, however, are not limited to thespecific embodiments presented in the detailed description, figures, andexamples. It should be recognized that these embodiments are merelyillustrative of the principles of the present disclosure. Numerousmodifications and adaptations will be readily apparent to those of skillin the art without departing from the spirit and scope of thedisclosure.

In addition, all ranges disclosed herein are to be understood toencompass any and all subranges subsumed therein. For example, a statedrange of “1.0 to 10.0” should be considered to include any and allsubranges beginning with a minimum value of 1.0 or more and ending witha maximum value of 10.0 or less, e.g., 1.0 to 5.3, or 4.7 to 10.0, or3.6 to 7.9.

All ranges disclosed herein are also to be considered to include the endpoints of the range, unless expressly stated otherwise. For example, arange of “between 5 and 10,” “from 5 to 10,” or “5-10” should generallybe considered to include the end points 5 and 10.

Further, when the phrase “up to” is used in connection with an amount orquantity, it is to be understood that the amount is at least adetectable amount or quantity. For example, a material present in anamount “up to” a specified amount can be present from a detectableamount and up to and including the specified amount.

The terms “three-dimensional printing system,” “three-dimensionalprinter,” “printing,” and the like generally describe various solidfreeform fabrication techniques for making three-dimensional articles orobjects by stereolithography, selective deposition, jetting, fuseddeposition modeling, multi-jet modeling, and other additivemanufacturing techniques now known in the art or that may be known inthe future that use a build material or ink to fabricatethree-dimensional objects.

I. Inks for 3D Printing

In one aspect, inks for use with a 3D printer are described herein. Insome embodiments, an ink described herein comprises a cyclopolymerizablemonomer. Additionally, an ink described herein, in some cases, furthercomprises one or more of the following: an oligomeric curable material,an additional monomeric curable material, at least one photoinitiator,at least one colorant, and one or more additives selected from the groupconsisting of inhibitors and stabilizing agents.

Turning now to specific components of inks, inks described hereincomprise a cyclopolymerizable monomer. The cyclopolymerizable monomercomprises a first ethenyl or ethynyl moiety and a second ethenyl orethynyl moiety. Further, the α-carbon of the first ethenyl or ethynylmoiety and the α-carbon of the second ethenyl or ethynyl moiety have a1,5-, 1,6-, 1,7-, or 1,8-relationship. In some cases, the first and/orsecond ethenyl moiety can be a vinyl moiety, an allyl moiety, or a(meth)acrylate moiety, where the term “(meth)acrylate” includes anacrylate or methacrylate, or a mixture or combination thereof. The firstand/or second ethynyl moiety, in some embodiments, is included in anacetylene or ethyne group or a propargyl group.

Additionally, in some embodiments, a cyclopolymerizable compound ormonomer described herein is neutrally charged or negatively charged, orcontains no cationic moieties. For instance, in some cases, acyclopolymerizable compound or monomer described herein does not includea quaternary ammonium moiety, particularly not in a portion of thecompound or monomer that does not directly participate incyclopolymerization or other polymerization of the compound, such asduring 3D printing.

Not intending to be bound by theory, it is believed that such a monomeras described above is capable of being cured or polymerized viacyclopoylmerization. For example, the first and second ethenyl orethynyl moieties of the monomer can be cyclopolymerized to form a 5, 6,7, or 8-membered ring. Cyclopolymerization of an exemplarycyclopolymerizable monomer described herein is shown in FIG. 1. Withoutintending to be bound by theory, it is further believed that thiscyclopolymerization may be at least partially responsible for theimproved mechanical characteristics observed in articles 3D-printedusing inks described herein, particularly when compared to otheracrylate-containing inks.

Moreover, again not intending to be bound by theory, it is furtherbelieved that cyclopolymerizable monomers described herein are alsocapable of being polymerized or cured via (meth)acrylate polymerizationor other polymerization of ethyleneically unsaturated moieties.Additionally, this second polymerization or curing pathway or mechanismcan be carried out by the first ethenyl or ethynyl moiety, the secondethenyl or ethynyl moiety, or both. This second polymerization or curingpathway is shown in FIG. 2. Such a “second” polymerization or curingpathway may also be carried out, in some cases, by an additionalethyleneically unsaturated moiety of the cyclopolymerizable monomer (ifsuch an additional moiety is present) that differs from the first andsecond ethenyl or ethynyl moieties.

Without intending to be bound by theory, it is believed that theexistence of this second polymerization or curing pathway may furtherimprove the properties of articles formed from an ink comprising acyclopolymerizable monomer described herein. Still not intending to bebound by theory, it is also believed that the ability of the same moietyor moieties of the cyclopolymerizable compound or monomer (i.e., thefirst and second ethenyl or ethynyl moieties) to participate in both ofthe polymerization or curing pathways above can provide additionaladvantages during a 3D printing process described herein.

Additionally, again without intending to be bound by theory, it isbelieved that the avoidance or absence of a cationic moiety such as aquaternary ammonium moiety described above, in some embodiments, canimprove the compatibility of a cyclopolymerizable compound or monomerdescribed herein with a 3D printing process, such as a process describedbelow in Section II.

Regarding specific suitable cyclopolymerizable monomers, in someembodiments, the cyclopolymerizable monomer of an ink described hereinhas the structure of Formula (I):

wherein:R₁ is a hydrocarbon group having 1-4 carbon atoms;R₂ is a hydrocarbon group having 1-4 carbon atoms;the total number of carbon atoms of R₁ and R₂ does not exceed 5;R₃ is HC═CH₂ or C≡CH;R₄ is HC═CH₂ or C≡CH; andR₅ is an organic moiety having a molecular weight of 500 or less. Insome cases, R₅ is an organic moiety having a molecular weight of 300 orless or 200 or less. In some instances, R₅ is an organic moiety having amolecular weight of 25-500, 25-400, 25-300, 25-200, 50-500, 50-400,50-300, or 50-200.

Moreover, in some embodiments, R₅ is a polymerizable moiety or containsa polymerizable moiety. Any polymerizable moiety not inconsistent withthe objectives of the present disclosure can be included as R₅, or inR₅. In some cases, for example, the polymerizable moiety is anethyleneically unsaturated moiety such as a (meth)acrylate moiety, vinylmoiety, or allyl moiety.

In some exemplary embodiments, R₅ is an organic moiety having one of thefollowing structures:

wherein R₆ is a substituted or unsubstituted hydrocarbon group having1-30 carbon atoms. In some cases, R₆ includes a polymerizable moietysuch as an ethyleneically unsaturated moiety (e.g., a (meth)acrylate,vinyl, or allyl moiety).

In other embodiments, the cyclopolymerizable monomer of an ink describedherein has the structure of Formula (II), which may be considered, insome cases, to be a “dimer” of the structure of Formula (I). Thestructure of Formula (II) is as follows:

wherein:R₁ is a hydrocarbon group having 1-4 carbon atoms;R₂ is a hydrocarbon group having 1-4 carbon atoms;the total number of carbon atoms of R₁ and R₂ does not exceed 5;R₃ is HC═CH₂ or C≡CH;R₄ is HC═CH₂ or C≡CH;R₅ is a hydrocarbon group having 1-30 carbon atoms or a poly(alkyleneglycol) having 2-30 alkylene glycol repeating units;R₇ is a hydrocarbon group having 1-4 carbon atoms;R₈ is a hydrocarbon group having 1-4 carbon atoms;the total number of carbon atoms of R₇ and R₈ does not exceed 5;R₉ is HC═CH₂ or C≡CH; andR₁₀ is HC═CH₂ or C≡CH.

In some preferred embodiments, R₅ in Formula (II) is a poly(alkyleneglycol) having 2-30 alkylene glycol repeating units cases. In otherinstances, R₅ in Formula (II) is a substituted or unsubstituted benzenering or phenyl moiety, such as a tolyl moiety.

Moreover, in some specific embodiments, R₁ and R₂ in Formula (I), andR₁, R₂, R₇, and R₈ in Formula (II), are each, individually, ahydrocarbon group having 1-3 carbon atoms or 1-2 carbon atoms.Additionally, it is to be understood that R₁ and R₂ (and R₇ and R₈) maybe the same or different. In one preferred embodiment, R₁ and R₂ (or R₁,R₂, R₇, and R₈) are each, individually, linear, saturated hydrocarbongroups having 1 or 2 carbon atoms, and the total number of carbon atomsof R₁ and R₂ (and/or the total number of carbon atoms of R₇ and R₈) doesnot exceed 4.

It is further to be understood that any hydrocarbon group in Formula (I)or Formula (II) above (including as part of R₅ or R₆) can be branched orlinear, saturated or unsaturated, and the hydrocarbon group may containor be a saturated or unsaturated, substituted or un-substitutedhydrocarbon ring.

Additional embodiments of cyclopolymerizable monomers described hereincan be found in the specific Examples section hereinbelow.

The above-described cyclopolymerizable monomer can be present in an inkdescribed herein in any amount not inconsistent with the objectives ofthe present disclosure. In some cases, the cyclopolymerizable monomer,in total, is present in the ink in an amount up to about 70 wt. %, up toabout 60 wt. %, up to about 50 wt. %, up to about 40 wt. %, up to about30 wt. %, up to about 20 wt. %, or up to about 10 wt. %, based on thetotal weight of the ink. In some instances, an ink described hereincomprises about 10-70 wt. % of the cyclopolymerizable monomer, based onthe total weight of the ink. In some embodiments, an ink comprises about10-60 wt. %, 10-50 wt. %, 10-40 wt. %, 10-30 wt. %, 10-20 wt. %, 20-70wt. %, 20-60 wt. %, 20-50 wt. %, 20-45 wt. %, 20-40 wt. %, 20-35 wt. %,or 20-30 wt. % of the cyclopolymerizable monomer, based on the totalweight of the ink.

Turning now to other specific components of inks described herein, inksdescribed herein may further comprise one or more oligomeric curablematerials and/or one or more additional monomeric curable materials(where the additional monomeric curable material is “additional”relative to the cyclopolymerizable monomer described above). However, itis to be understood that one or more of such other ink components (i.e.,oligomeric curable materials and/or additional monomeric curablematerials) are not necessarily present in all ink compositions describedherein.

A curable material, for reference purposes herein, comprises a chemicalspecies that includes one or more curable or polymerizable moieties. A“polymerizable moiety,” for reference purposes herein, comprises amoiety that can be polymerized or cured to provide a printed 3D articleor object. Such polymerizing or curing can be carried out in any mannernot inconsistent with the objectives of the present disclosure. In someembodiments, for example, polymerizing or curing comprises irradiating apolymerizable or curable material with electromagnetic radiation havingsufficient energy to initiate a polymerization or cross-linkingreaction. For instance, in some cases, ultraviolet (UV) radiation can beused. Thus, in some instances, a polymerizable moiety comprises aphoto-polymerizable or photo-curable moiety, such as a UV-polymerizablemoiety. In some embodiments, a curable material described herein isphoto-polymerizable or photo-curable at wavelengths ranging from about300 nm to about 400 nm or from about 320 nm to about 380 nm.Alternatively, in other instances, a curable material isphoto-polymerizable at visible wavelengths of the electromagneticspectrum.

Moreover, a polymerization reaction, in some cases, comprises a freeradical polymerization reaction, such as that between points ofunsaturation, including points of ethyleneic unsaturation. Otherpolymerization reactions may also be used. As understood by one ofordinary skill in the art, a polymerization reaction used to polymerizeor cure a curable material described herein can comprise a reaction of aplurality of “monomers” or chemical species having one or morefunctional groups or moieties that can react with one another to formone or more covalent bonds.

One non-limiting example of a polymerizable moiety of a curable materialdescribed herein is an ethyleneically unsaturated moiety, such as avinyl moiety, allyl moiety, or (meth)acrylate moiety, where the term“(meth)acrylate” includes acrylate or methacrylate or a mixture orcombination thereof.

“Oligomeric” species, which are contained in the oligomeric curablematerial described herein, are themselves polymers or oligomers and havea relatively high molecular weight or a relatively high viscosity. Thesespecies are also capable of undergoing additional polymerization, suchas through one or more points of unsaturation described herein. Apopulation of oligomeric species in the oligomeric curable materialdescribed herein can have varying molecular structures and/or formulasthroughout the population (such as may be exhibited, for example, by aspecified mass of a urethane acrylate having a non-unity molecularweight distribution, or by a specified mass of an ethoxylatedpolyethylene glycol having a distribution of ethylene glycol unitsand/or a distribution of ethoxy units within the population). The weightaverage molecular weight of an oligomeric curable material describedherein can generally be in the range from about 400 to 10,000, fromabout 600 to 10,000, or from about 500 to 7,000.

In contrast to an “oligomeric” species, “monomeric” species, which arecontained in the additional monomeric material described herein, are notthemselves a polymer or oligomer, and have a relatively low molecularweight or a relatively low viscosity. “Monomeric” species contained inthe additional monomeric curable material can have a consistent orwell-defined molecular structure and/or formula throughout thepopulation (such as may be exhibited, for instance, by a specified massof ethoxylated (4) bisphenol A diacrylate or a specific mass of theabove-described curable monomer). Additionally, in some embodiments, anadditional monomeric curable material as described herein has aviscosity of 500 centipoise (cP) or less at 25° C., when measuredaccording to ASTM D2983, while an “oligomeric” curable material has aviscosity of 1000 cP or more at 25° C., when measured according to ASTMD2983.

One non-limiting example of a polymerizable moiety of the oligomericcurable material or the additional monomeric curable material describedherein is an ethylenically unsaturated moiety, such as a vinyl moiety,allyl moiety, or (meth)acrylate moiety, where the term “(meth)acrylate”includes acrylate or methacrylate or a mixture or combination thereof.

Additionally, the oligomeric curable material and the additionalmonomeric curable material described herein can comprise amonofunctional, difunctional, trifunctional, tetrafunctional,pentafunctional, or higher functional curable species. A“monofunctional” curable species, for reference purposes herein,comprises a chemical species that includes one curable or polymerizablemoiety. Similarly, a “difunctional” curable species comprises a chemicalspecies that includes two curable or polymerizable moieties; a“trifunctional” curable species comprises a chemical species thatincludes three curable or polymerizable moieties; a “tetrafunctional”curable species comprises a chemical species that includes four curableor polymerizable moieties; and a “pentafunctional” curable speciescomprises a chemical species that includes five curable or polymerizablemoieties. Thus, in some embodiments, a monofunctional curable materialof an ink described herein comprises a mono(meth)acrylate, adifunctional curable material of an ink described herein comprises adi(meth)acrylate, a trifunctional curable material of an ink describedherein comprises a tri(meth)acrylate, a tetrafunctional curable materialof an ink described herein comprises a tetra(meth)acrylate, and apentafunctional curable material of an ink described herein comprises apenta(meth)acrylate. Other monofunctional, difunctional, trifunctional,tetrafunctional, and pentafunctional curable materials may also be used.

Moreover, a monofunctional, difunctional, trifunctional,tetrafunctional, and pentafunctional curable material, in some cases,can comprise a relatively low molecular weight species, i.e., amonomeric species, or a relatively high molecular weight species, i.e.,an oligomeric species.

In general, any oligomeric curable material not inconsistent with theobjectives of the present disclosure may be used in an ink describedherein. In some cases, for instance, an oligomeric curable materialcomprises a polyester (meth)acrylate oligomer, a urethane (meth)acrylateoligomer, or an epoxy(meth)acrylate oligomer. Further, in someembodiments, an oligomeric curable material described herein comprisesan aliphatic polyester urethane acrylate oligomer and/or an acrylateamine oligomeric resin, such as EBECRYL 7100. In some cases, anoligomeric curable material described herein comprises a polypropyleneglycol mono(meth)acrylate or polyethylene glycol mono(meth)acrylate. Insome embodiments, an oligomeric curable material comprises amonofunctional aliphatic urethane (meth)acrylate. Moreover, in somecases, an oligomeric curable material comprises a diacrylate and/ordimethacrylate ester of an aliphatic, cycloaliphatic or aromatic diol,including polyethylene glycol, ethoxylated or propoxylated neopentylglycol, ethoxylated or propoxylated bisphenol A, ethoxylated orpropoxylated bisphenol F, ethoxylated or propoxylated bisphenol S,ethoxylated or propoxylated 1,1,1-trimethylolpropanetri(meth)acrylate,or ethoxylated or propoxylated glycerol tri(meth)acrylate.

Moreover, an oligomeric curable material consistent with the objectivesof the present disclosure, in some instances, does not include a polymeror oligomer comprising or formed from one or more structural unitsderived from a cyclopolymerizable monomer as described herein, e.g., acyclopolymerizable monomer according to Formula (I) or Formula (II).Similarly, in some cases, the oligomeric curable material does notinclude a polymer or oligomer comprising structural units derived from acyclopolymerizable monomer as described herein (e.g., acyclopolymerizable monomer according to Formula (I) or Formula (II)),and at least one monomer selected from the group consisting of(meth)acrylic ester, (meth)acrylamide, unsaturated monocarboxylic acid,and aromatic vinyl and N-substituted maleimide. Instead, in somepreferred embodiments, inks described herein contain acyclopolymerizable monomer as described herein (e.g., acyclopolymerizable monomer according to Formula (I) or Formula (II)),only as a monomeric curable material prior to curing.

Some non-limiting examples of commercially available oligomeric curablematerials useful in some embodiments described herein include thefollowing: alkoxylated tetrahydrofurfuryl acrylate, commerciallyavailable from SARTOMER under the trade name SR 611; monofunctionalurethane acrylate, commercially available from RAHN USA under the tradename GENOMER 1122; an aliphatic urethane diacrylate, commerciallyavailable from ALLNEX under the trade name EBECRYL 8402; amultifunctional acrylate oligomer, commercially available from DYMAXCorporation under the trade name BR-952; and aliphatic polyetherurethane acrylate, commercially available from DYMAX Corporation underthe trade name BR-371S. Other commercially available oligomeric curablematerials may also be used.

Urethane (meth)acrylates suitable for use in inks described herein, insome cases, can be prepared in a known manner, typically by reacting ahydroxyl-terminated urethane with acrylic acid or methacrylic acid togive the corresponding urethane (meth)acrylate, or by reacting anisocyanate-terminated prepolymer with hydroxyalkyl acrylates ormethacrylates to give the urethane (meth)acrylate. Suitable processesare disclosed, inter alia, in EP-A 114 982 and EP-A 133 908. The weightaverage molecular weight of such (meth)acrylate oligomers, in somecases, can be from about 400 to 10,000 or from about 500 to 7,000.Urethane (meth)acrylates are also commercially available from SARTOMERunder the product names CN980, CN981, CN975 and CN2901, or from BOMARSpecialties Co. under the product name BR-741. In some embodimentsdescribed herein, a urethane (meth)acrylate oligomer has a viscosityranging from about 140,000 centipoise (cP) to about 160,000 cP at about50° C. or from about 125,000 cP to about 175,000 cP at about 50° C. whenmeasured in a manner consistent with ASTM D2983. In some cases, aurethane (meth)acrylate oligomer has a viscosity ranging from about100,000 cP to about 200,000 cP at about 50° C. or from about 10,000 cPto about 300,000 cP at about 50° C. when measured in a manner consistentwith ASTM D2983.

The oligomeric curable material can be present in an ink describedherein in any amount not inconsistent with the objectives of the presentdisclosure (if it is present at all). In some cases, the oligomericcurable material, in total, is present in the ink in an amount up toabout 70 wt. %, up to about 60 wt. %, up to about 50 wt. %, up to about40 wt. %, up to about 30 wt. %, or up to about 20 wt. %, based on thetotal weight of the ink. In some instances, an ink described hereincomprises about 10-70 wt. % of the oligomeric curable material, based onthe total weight of the ink. In some embodiments, an ink comprises about10-60 wt. %, 10-50 wt. %, 10-40 wt. %, 10-30 wt. %, 10-20 wt. %, 15-40wt. %, 15-30 wt. %, 20-60 wt. %, 20-50 wt. %, 20-40 wt. %, 30-60 wt. %,30-50 wt. %, or 40-60 wt. % of the oligomeric curable material, based onthe total weight of the ink. Alternatively, in other embodiments, anoligomeric curable material is not present in an ink described herein.

In addition, any monomeric curable materials not inconsistent with theobjectives of the present disclosure may be used as the additionalmonomeric curable material described herein. In some cases, theadditional monomeric curable material of an ink described hereincomprises one or more species of (meth)acrylates, such as one or moremonofunctional, difunctional, trifunctional, tetrafunctional(meth)acrylates, and/or pentafunctional (meth)acrylates. In someembodiments, for instance, a monomeric curable material comprises methyl(meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl(meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate,2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl(meth)acrylate, n-dodecyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate,2- or 3-hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate,2-ethoxyethyl (meth)acrylate, 2- or 3-ethoxypropyl (meth)acrylate,tetrahydrofurfuryl methacrylate, isobornyl (meth)acrylate,2-(2-ethoxyethoxy)ethyl acrylate, cyclohexyl methacrylate,2-phenoxyethyl acrylate, glycidyl acrylate, isodecyl acrylate,2-phenoxyethyl (meth)acrylate, lauryl methacrylate, or a combinationthereof. In some embodiments, a monomeric curable material comprises oneor more of allyl acrylate, allyl methacrylate, triethylene glycoldi(meth)acrylate, tricyclodecane dimethanol diacrylate, and cyclohexanedimethanol diacrylate. Additionally, in some cases, a monomeric curablematerial comprises diacrylate and/or dimethacrylate esters of aliphatic,cycloaliphatic or aromatic diols, including 1,3- or 1,4-butanediol,neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol,tetraethylene glycol, tripropylene glycol,1,4-dihydroxymethylcyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane orbis(4-hydroxycyclohexyl)methane, hydroquinone, 4,4′-dihydroxybiphenyl,bisphenol A, bisphenol F, or bisphenol S. A monomeric curable materialdescribed herein may also comprise 1,1-trimethylolpropanetri(meth)acrylate, pentaerythritol monohydroxy tri(meth)acrylate,dipentaerythritol monohydroxy penta(meth)acrylate, and/orbis(trimethylolpropane) tetra(meth)acrylate. Further, in some cases, amonomeric curable material can comprise an ethoxylated or propoxylatedspecies, such as ethoxylated or propoxylated neopentyl glycol,ethoxylated or propoxylated bisphenol A, ethoxylated or propoxylatedbisphenol F, ethoxylated or propoxylated bisphenol S, ethoxylated orpropoxylated 1,1,1-trimethylolpropanetri(meth)acrylate, or ethoxylatedor propoxylated glycerol tri(meth)acrylate.

Additional non-limiting examples of commercially available monomericcurable materials useful as the additional monomeric curable material insome embodiments described herein include the following: isobornylacrylate (IBOA), commercially available from SARTOMER under the tradename SR 506; isobornyl methacrylate, commercially available fromSARTOMER under the trade name SR 423A; triethylene glycol diacrylate,commercially available from SARTOMER under the trade name SR 272;triethylene glycol dimethacrylate, commercially available from SARTOMERunder the trade name SR 205; tricyclodecane dimethanol diacrylate,commercially available from SARTOMER under the trade name SR 833S;tris(2-hydroxy ethyl)isocyanurate triacrylate, commercially availablefrom SARTOMER under the trade name SR 368; 2-phenoxyethyl acrylate,commercially available from SARTOMER under the trade name SR 339;ethyoxylated (3 mole) bisphenol A diacrylate, commercially availablefrom SARTOMER under the trade name SR 349; a cyclic monofunctionalacrylate, commercially available by RAHN USA Corp. under the trade nameGENOMER 1120; and dipentaerythritol pentaacrylate, commerciallyavailable from SARTOMER under the trade name SR 399 LV. Othercommercially available monomeric curable materials may also be used.

The additional monomeric curable material can be present in an inkdescribed herein in any amount not inconsistent with the objectives ofthe present disclosure (if it is present at all). In some cases, themonomeric curable material, in total, is present in an amount up toabout 80 wt. %, up to about 70 wt. %, up to about 60 wt. %, or up toabout 50 wt. %, based on the total weight of the ink. In some cases, anink described herein comprises about 0-80 wt. % additional monomericcurable material, based on the total weight of the ink. In someembodiments, an ink comprises about 0-75 wt. %, 0-70 wt. %, 0-60 wt. %,0-50 wt. %, 0-40 wt. %, 0-35 wt. %, 0-30 wt. %, 0-25 wt. %, 0-20 wt. %,0-15 wt. %, 0-10 wt. %, or 0-5 wt. % additional monomeric curablematerial, based on the total weight of the ink. Alternatively, in somecases, an additional monomeric curable material is not present in an inkdescribed herein.

Moreover, with respect to oligomeric curable materials and additionalmonomeric curable materials described above, it is to be understood thatthese components of the ink can vary in type and/or in quantity withoutsubstantially changing desired improvements provided bycyclopolymerizable monomers described herein.

Turning to another component of inks described herein, inks describedherein can further comprise at least one photoinitiator. Anyphotoinitiator not inconsistent with the objectives of the presentdisclosure may be used. In some cases, a photoinitiator comprises analpha-cleavage type (unimolecular decomposition process) photoinitiatoror a hydrogen abstraction photosensitizer-tertiary amine synergist,operable to absorb light between about 250 nm and about 400 nm orbetween about 300 nm and about 385 nm, to yield free radical(s).Examples of alpha cleavage photoinitiators are Irgacure 184 (CAS947-19-3), Irgacure 369 (CAS 119313-12-1), and Irgacure 819 (CAS162881-26-7). An example of a photosensitizer-amine combination isDarocur BP (CAS 119-61-9) with diethylaminoethylmethacrylate.

In addition, in some instances, photoinitiators comprise benzoins,including benzoin, benzoin ethers, such as benzoin methyl ether, benzoinethyl ether and benzoin isopropyl ether, benzoin phenyl ether andbenzoin acetate, acetophenones, including acetophenone,2,2-dimethoxyacetophenone and 1,1-dichloroacetophenone, benzil, benzilketals, such as benzil dimethyl ketal and benzil diethyl ketal,anthraquinones, including 2-methylanthraquinone, 2-ethylanthraquinone,2-tert-butylanthraquinone, 1-chloroanthraquinone and2-amylanthraquinone, triphenylphosphine, benzoylphosphine oxides, suchas 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO),benzophenones, such as benzophenone and4,4′-bis(N,N′-dimethylamino)benzophenone, thioxanthones and xanthones,acridine derivatives, phenazine derivatives, quinoxaline derivatives or1-phenyl-1,2-propanedione, 2-O-benzoyl oxime, 1-aminophenyl ketones or1-hydroxyphenyl ketones, such as 1-hydroxycyclohexyl phenyl ketone,phenyl 1-hydroxyisopropyl ketone and 4-isopropylphenyl1-hydroxyisopropyl ketone.

Photoinitiators can also comprise photoinitiators operable for use witha HeCd laser radiation source, including acetophenones,2,2-dialkoxybenzophenones and 1-hydroxyphenyl ketones, such as1-hydroxycyclohexyl phenyl ketone or 2-hydroxyisopropyl phenyl ketone(=2-hydroxy-2,2-dimethylacetophenone). Additionally, in some cases,photoinitiators comprise photoinitiators operable for use with an Arlaser radiation source including benzil ketals, such as benzil dimethylketal. In some embodiments, a suitable photoinitiator comprises anα-hydroxyphenyl ketone, benzil dimethyl ketal or2,4,6-trimethylbenzoyldiphenylphosphine oxide or a mixture thereof.

Another class of photoinitiators that may be included in an inkdescribed herein comprises ionic dye-counter ion compounds capable ofabsorbing actinic radiation and generating free radicals forpolymerization initiation. Some ionic dye-counter ion compounds andtheir mode of operation are disclosed in EP-A-0 223 587 and U.S. Pat.Nos. 4,751,102; 4,772,530; and 4,772,541.

A photoinitiator can be present in an ink described herein in any amountnot inconsistent with the objectives of the present disclosure. In someembodiments, a photoinitiator is present in an ink in an amount of up toabout 5 wt. %, based on the total weight of the ink. In some cases, aphotoinitiator is present in an amount ranging from about 0.1 wt. % toabout 5 wt. %. It is also possible, in some instances, for an inkdescribed herein to include no photoinitiator, where it is understoodthat the photoinitiator is a photoinitiator of curing of a curablematerial or monomer described herein, such as an oligomeric curablematerial, an additional monomeric curable material, or acyclopolymerizable monomer.

Additionally, in some embodiments, an ink described herein furthercomprises one or more photosensitizers. In general, such a sensitizercan be added to an ink to increase the effectiveness of one or morephotoinitiators that may also be present. In some cases, a sensitizercomprises isopropylthioxanthone (ITX) or 2-chlorothioxanthone (CTX).

A sensitizer can be present in an ink in any amount not inconsistentwith the objectives of the present disclosure. In some embodiments, asensitizer is present in an amount ranging from about 0.1 wt. % to about2 wt. % or from about 0.5 wt. % to about 1 wt. %, based on the totalweight of the ink.

Turning to another component of the ink described herein, inks describedherein can also comprise at least one colorant. The colorant of an inkdescribed herein can be a particulate colorant, such as a particulatepigment, or a molecular colorant, such as a molecular dye. Any suchparticulate or molecular colorant not inconsistent with the objectivesof the present disclosure may be used. In some cases, for instance, thecolorant of an ink comprises an inorganic pigment, such as TiO₂ and/orZnO. In some embodiments, the colorant of an ink comprises a colorantfor use in a RGB, sRGB, CMY, CMYK, L*a*b*, or Pantone® colorizationscheme. In some instances, one or more colorants of an ink describedherein exhibits a white color. In other cases, a colorant exhibits ablack color. Some non-limiting examples of colorants suitable for use insome embodiments described herein include SUN UVDJ107, SUN UVDJ1 50, SUNUVDJ322, SUN UVDJ350, SUN UVDJ354, RJA D3010-FX-Y1 50, RJA D3410-FX-Y150, RJA D3410-FX-K, PENN COLOR 96898, PENN COLOR 96989, DNS-GKC-103W,and Ob White Dye. Moreover, in some cases, a particulate colorantdescribed herein has an average particle size of less than about 5 μm,or less than about 1 μm. In some instances, a particulate colorantdescribed herein has an average particle size of less than about 500 nm,such as an average particle size of less than about 400 nm, less thanabout 300 nm, less than about 250 nm, less than about 200 nm, or lessthan about 150 nm. In some instances, a particulate colorant has anaverage particle size of about 50-5000 nm, about 50-1000 nm, or about50-500 nm.

A colorant can be present in an ink described herein in any amount notinconsistent with the objectives of the present disclosure. In somecases, colorant is present in the ink in an amount up to about 2 wt. %,or an amount of about 0.005-2 wt. %, 0.01-2 wt. %, 0.01-1.5 wt. %,0.01-1 wt. %, 0.01-0.5 wt. %, 0.1-2 wt. %, 0.1-1 wt. %, 0.1-0.5 wt. %,or 0.5-1.5 wt. %, based on the total weight of the ink. It is alsopossible for an ink described herein to not include a colorant.

Moreover, inks described herein, in some embodiments, further compriseone or more other additives. In some cases, for example, an inkdescribed herein further comprises one or more polymerization inhibitorsand/or stabilizing agents. A polymerization inhibitor can be added to anink to provide additional thermal stability to the composition. Anypolymerization inhibitor not inconsistent with the objectives of thepresent disclosure may be used. Moreover, a polymerization inhibitor canretard or decrease the rate of polymerization, and/or preventpolymerization from occurring for some period of time or “inductiontime” until the polymerization inhibitor is consumed. Further, in somecases, a polymerization inhibitor described herein is an “addition type”inhibitor. An inhibitor described herein can also be a “chain transfertype” inhibitor. In some instances, a suitable polymerization inhibitorcomprises methoxyhydroquinone (MEHQ).

A stabilizing agent, in some embodiments, comprises one or moreanti-oxidants. A stabilizing agent can comprise any anti-oxidant notinconsistent with the objectives of the present disclosure. In somecases, suitable anti-oxidants include various aryl compounds, includingbutylated hydroxytoluene (BHT), which can also be used as apolymerization inhibitor in some embodiments described herein. Moregenerally, a single species may serve as both a stabilizing agent and apolymerization inhibitor. It is also possible, in some cases, to use aplurality of inhibitors and/or stabilizing agents, wherein differinginhibitors and/or stabilizers provide differing effects and/or worksynergistically.

A polymerization inhibitor and/or a stabilizing agent can be present inan ink in any amount not inconsistent with the objectives of the presentdisclosure. In some embodiments, a polymerization inhibitor is presentin an amount ranging from about 0.01 wt. % to about 2 wt. % or fromabout 0.05 wt. % to about 1 wt. %. Similarly, in some cases, astabilizing agent is present in an ink in an amount ranging from about0.1 wt. % to about 5 wt. %, from about 0.5 wt. % to about 4 wt. %, orfrom about 1 wt. % to about 3 wt. %, based on the total weight of theink. It is also possible for an ink described herein to exclude apolymerization inhibitor and/or a stabilizing agent.

In some embodiments, an ink described herein may contain viscositymodifying agents. Non-limiting examples of viscosity modifying agentsinclude a saturated fatty acid or a combination of saturated fattyacids, or an oil, such as a plant oil. The inks described herein maycomprise up to 5 wt. % up to 3 wt. %, up to 1 wt. %, up to 0.5 wt. %, orup to 0.1 wt. % of a viscosity modifying agent not inconsistent with theobjectives of the present disclosure. Alternatively, in some instances,a viscosity modifying agent is not present in an ink described herein.

Inks described herein can exhibit a variety of desirable properties. Forexample, an ink described herein can have any freezing point, meltingpoint, and/or other phase transition temperature not inconsistent withthe objectives of the present disclosure. In some cases, an ink hasfreezing and melting points consistent with temperatures used in some 3Dprinting systems, including 3D printing systems designed for use withphase changing inks. In some embodiments, the freezing point of an inkis greater than about 40° C. In some instances, for example, an ink hasa freezing point centered at a temperature ranging from about 45° C. toabout 55° C. or from about 50° C. to about 80° C. In some cases, an inkhas a freezing point below about 40° C. or below about 30° C.

Further, in some embodiments described herein, an ink exhibits a sharpfreezing point or other phase transition. In some cases, for instance,an ink freezes over a narrow range of temperatures, such as a range ofabout 1-10° C., about 1-8° C., or about 1-5° C. In some embodiments, anink having a sharp freezing point freezes over a temperature range ofX±2.5° C., where X is the temperature at which the freezing point iscentered (e.g., X=65° C.).

In addition, an ink described herein, in some cases, is fluid at jettingtemperatures encountered in some 3D printing systems. Moreover, in someembodiments, an ink solidifies once deposited on a surface during thefabrication of a three-dimensionally printed article or object.Alternatively, in other instances, an ink remains substantially fluidupon deposition on a surface. Solidification of an ink, in someembodiments, occurs through a phase change of the ink or a component ofthe ink. The phase change can comprise a liquid to solid phase change ora liquid to semi-solid phase change. Further, in some instances,solidification of an ink comprises an increase in viscosity of the ink,such as an increase in viscosity from a low viscosity state to a highviscosity state. Solidification of an ink can also occur due to curingof the ink.

Additionally, in some embodiments, the inks described herein, whennon-cured, has a viscosity profile consistent with the requirements andparameters of one or more 3D printing systems, such as an MJP or SLAsystem. For example, in some cases, an ink described herein has adynamic viscosity at 30° C. of 1600 centipoise (cP) or less, 1200 cP orless, or 800 cP or less. In a preferred embodiment, an ink describedherein has a dynamic viscosity of 500 cP or less at 30° C., whenmeasured according to ASTM standard D2983 (e.g., using a BrookfieldModel DV-II+ Viscometer). In some cases, an ink described herein whennon-cured exhibits a dynamic viscosity of about 200-1600 cP, about200-1200 cP, about 200-800 cP, about 200-500 cP, or about 200-400 cP at30° C., when measured according to ASTM D2983.

Inks described herein can also exhibit a variety of desirableproperties, in addition to those described hereinabove, in a curedstate. An ink in a “cured” state, as used herein, comprises an ink thatincludes a curable material or polymerizable component that has been atleast partially cured, i.e., at least partially polymerized and/orcross-linked. For instance, in some cases, a cured ink is at least about70% polymerized or cross-linked or at least about 80% polymerized orcross-linked. In some embodiments, a cured ink is at least about 85%, atleast about 90%, at least about 95%, at least about 98%, or at least 99%polymerized or cross-linked. In some instances, a cured ink is betweenabout 80% and about 99% polymerized or cross-linked.

In some cases, an ink described herein, when cured, has an elongation atbreak of about 10 to 70%, about 10 to 60%, about 15 to 50%, or about 20to 50%, when measured according to ASTM D638. Further, a cured inkdescribed herein, in some cases, can have a tensile strength of about 40to 70 MPa about 40 to 60 MPa, or about 45 to 55 MPa when measuredaccording to ASTM D638. Additionally, a cured ink described herein, insome embodiments, can have a tensile modulus of about 1800 to 2100 MPa,about 1900 to 2100 MPa, or about 1 950 to 2050 MPa when measuredaccording to ASTM D638. Also, a cured ink described herein can have animpact resistance of 1 to 4 ft·lb/in (Notched), 1 to 3 ft·lb/in(Notched), or 1 to 2 ft·lb/in (Notched) when measured according to ASTMD256. Finally, in some cases, a cured ink described herein has a flexualmodulus of 2000 to 2500 MPa, 2100 to 2400 MPa, or 2100 to 2200 MPa whenmeasured according to ASTM D790.

Moreover, in some cases, an ink described herein, when cured, canexhibit a plurality of the foregoing properties. For example, in someembodiments, an ink when cured has a tensile strength of about 40-70 MPawhen measured according to ASTM D638; an impact resistance of 1 to 4ft·lb/in (Notched), when measured according to ASTM D256; and anelongation at break of about 10-70% when measured according to ASTMD638. In some instances, an ink when cured has an impact resistance of40-120 J/m or 50-115 j/m, and also an elongation at break of 40-60% or40-50%, when measured as described herein.

It is to be understood that, in some instances, various components ofinks described herein (such as the oligomeric curable material, theadditional monomeric curable material, the photoinitiator, thephotosensitizer, the colorant, the polymerization inhibitor, thestabilizing agent, or the viscosity modifying agent) can vary in typeand/or in quantity without substantially changing desirable propertiesof inks described herein. For example, in some instances, changes in thespecific type and/or quantity of various components of the ink (that arewithin the scope of the disclosed types and quantities) affect desiredproperties of the ink, as described above, by 5% or less, 4% or less, 3%or less, 2% or less, or 1% or less. Thus, as described in the Examplesprovided below, in some instances, the type and quantity of thecyclopolymerizable monomer and/or other components of the ink can bevaried as desired from ink to ink without departing from an inkcomposition exhibiting any one or more of the desirable properties asdescribed herein.

Inks described herein can be produced in any manner not inconsistentwith the objectives of the present disclosure. In some embodiments, forinstance, a method for the preparation of an ink described hereincomprises the steps of mixing the components of the ink, melting themixture, and filtering the molten mixture. Melting the mixture, in somecases, is carried out at a temperature of about 75° C. or in a rangefrom about 75° C. to about 85° C. In some embodiments, an ink describedherein is produced by placing all components of the ink in a reactionvessel and heating the resulting mixture to a temperature ranging fromabout 75° C. to about 85° C. with stirring. The heating and stirring arecontinued until the mixture attains a substantially homogenized moltenstate. In general, the molten mixture can be filtered while in aflowable state to remove any large undesirable particles that mayinterfere with jetting or extrusion or other printing process. Thefiltered mixture can then be cooled to ambient temperatures and storeduntil ready for use in a 3D printing system.

II. Methods of Printing a 3D Article

In another aspect, methods of printing a 3D article or object aredescribed herein. Methods of printing a 3D article or object describedherein can include forming the 3D article from a plurality of layers ofan ink described herein in a layer-by-layer manner. Any ink describedhereinabove in Section I may be used. For example, in some cases, theink comprises 10-70 wt. % or 20-40 wt. % of a cyclopolymerizable monomerdescribed in Section I above, based on the total weight of the ink.Additionally, in some embodiments, the ink has a dynamic viscosity of1,600 cP or less or 500 cP or less at 30° C. Further, the layers of anink can be deposited according to an image of the 3D article in acomputer readable format. In some embodiments, the ink is depositedaccording to preselected computer aided design (CAD) parameters.Moreover, in some cases, one or more layers of an ink described hereinhas a thickness of about 10 μm to about 100 μm, about 10 μm to about 80μm, about 10 μm to about 50 μm, about 20 μm to about 100 μm, about 20 μmto about 80 μm, or about 20 μm to about 40 μm. Other thicknesses arealso possible.

Additionally, it is to be understood that methods of printing a 3Darticle described herein can include, for example, MJP or SLA 3Dprinting methods. For example, in some instances, a MJP method ofprinting a 3D article comprises selectively depositing layers of an inkdescribed herein in a fluid state onto a substrate, such as a build padof a 3D printing system. In addition, in some embodiments, a methoddescribed herein further comprises supporting at least one of the layersof the ink with a support material. Any support material notinconsistent with the objectives of the present disclosure may be used.

A method described herein can also comprise curing the layers of theink. For example, in some instances, a method of printing a 3D articledescribed herein further comprises subjecting the ink to electromagneticradiation of sufficient wavelength and intensity to cure the ink, wherecuring can comprise polymerizing one or more polymerizable moieties orfunctional groups of one or more components of the ink. In some cases, alayer of deposited ink is cured prior to the deposition of another oradjacent layer of ink. Additionally, curing one or more layers ofdeposited ink, in some embodiments, is carried out by exposing the oneor more layers to electromagnetic radiation, such as UV light, visiblelight, or infrared light.

Further details regarding various methods, including “materialdeposition” methods (such as MJP) or “vat polymerization” methods (suchas SLA), are provided below.

A. Material Deposition Methods

In a material deposition method, one or more layers of an ink describedherein are selectively deposited onto a substrate and cured. Curing ofthe ink may occur after selective deposition of one layer, each layer,several layers, or all layers of the ink.

In some instances, an ink described herein is selectively deposited in afluid state onto a substrate, such as a build pad of a 3D printingsystem. Selective deposition may include, for example, depositing theink according to preselected CAD parameters. For example, in someembodiments, a CAD file drawing corresponding to a desired 3D article tobe printed is generated and sliced into a sufficient number ofhorizontal slices. Then, the ink is selectively deposited, layer bylayer, according to the horizontal slices of the CAD file drawing toprint the desired 3D article. A “sufficient” number of horizontal slicesis the number necessary for successful printing of the desired 3Darticle, e.g., to produce it accurately and precisely.

Further, in some embodiments, a preselected amount of ink describedherein is heated to the appropriate temperature and jetted through aprint head or a plurality of print heads of a suitable inkjet printer toform a layer on a print pad in a print chamber. In some cases, eachlayer of ink is deposited according to preselected CAD parameters. Asuitable print head to deposit the ink, in some embodiments, is apiezoelectric print head. Additional suitable print heads for thedeposition of ink and support material described herein are commerciallyavailable from a variety of ink jet printing apparatus manufacturers.For example, Xerox, Hewlett Packard, or Ricoh print heads may be used insome instances.

Additionally, in some embodiments, an ink described herein remainssubstantially fluid upon deposition. Alternatively, in other instances,the ink exhibits a phase change upon deposition and/or solidifies upondeposition. Moreover, in some cases, the temperature of the printingenvironment can be controlled so that the jetted droplets of inksolidify on contact with the receiving surface. In other embodiments,the jetted droplets of ink do not solidify on contact with the receivingsurface, remaining in a substantially fluid state. Additionally, in someinstances, after each layer is deposited, the deposited material isplanarized and cured with electromagnetic (e.g., UV, visible or infraredlight) radiation prior to the deposition of the next layer. Optionally,several layers can be deposited before planarization and curing, ormultiple layers can be deposited and cured followed by one or morelayers being deposited and then planarized without curing. Planarizationcorrects the thickness of one or more layers prior to curing thematerial by evening the dispensed material to remove excess material andcreate a uniformly smooth exposed or flat up-facing surface on thesupport platform of the printer. In some embodiments, planarization isaccomplished with a wiper device, such as a roller, which may becounter-rotating in one or more printing directions but notcounter-rotating in one or more other printing directions. In somecases, the wiper device comprises a roller and a wiper that removesexcess material from the roller. Further, in some instances, the wiperdevice is heated. It should be noted that the consistency of the jettedink described herein prior to curing, in some embodiments, shoulddesirably be sufficient to retain its shape and not be subject toexcessive viscous drag from the planarizer.

Moreover, a support material, when used, can be deposited in a mannerconsistent with that described hereinabove for the ink. The supportmaterial, for example, can be deposited according to the preselected CADparameters such that the support material is adjacent or continuous withone or more layers of the ink. Jetted droplets of the support material,in some embodiments, solidify or freeze on contact with the receivingsurface. In some cases, the deposited support material is also subjectedto planarization, curing, or planarization and curing. Any supportmaterial not inconsistent with the objectives of the present disclosuremay be used.

Layered deposition of the ink and support material can be repeated untilthe 3D article has been formed. In some embodiments, a method ofprinting a 3D article further comprises removing the support materialfrom the ink.

Curing of the ink may occur after selective deposition of one layer ofink, of each layer of ink, of several layers of ink, or of all layers ofthe ink necessary to print the desired 3D article. In some embodiments,a partial curing of the deposited ink is performed after selectivedeposition of one layer of ink, each layer of ink, several layers ofink, or all layers of the ink necessary to print the desired 3D article.A “partially cured” ink, for reference purposes herein, is one that canundergo further curing. For example, a partially cured ink is up toabout 30% polymerized or cross-linked or up to about 50% polymerized orcross-linked. In some embodiments, a partially cured ink is up to about60%, up to about 70%, up to about 80%, up to about 90%, or up to about95% polymerized or cross-linked.

In some embodiments, partial curing of the deposited ink can includeirradiating the ink with an electromagnetic radiation source orphotocuring the ink. Any electromagnetic radiation source notinconsistent with the objectives of the present disclosure may be used,e.g., an electromagnetic radiation source that emits UV, visible orinfrared light. For example, in some embodiments, the electromagneticradiation source can be one that emits light having a wavelength fromabout 300 nm to about 900 nm, e.g., a Xe arc lamp.

Moreover, in some embodiments, partial curing of an ink described hereinincludes polymerizing the first ethenyl or ethynyl moiety, the secondethenyl or ethynyl moiety, and/or a (meth)acrylate moiety of thecyclopolymerizable monomer via alkene, alkyne, and/or (meth)acrylatepolymerization. In some cases, partial curing primarily includes such(meth)acrylate polymerization. For example, in some instances, more than50%, more than 60%, or more than 70% of the polymerization occurs via(meth)acrylate polymerization, rather than via some other polymerizationroute, e.g., cyclopolymerization of the first and second ethenyl orethynyl moieties of the ink. During partial curing, which is performedduring the build of a desired 3D article, some or none of thepolymerization may occur via a route other than a (meth)acrylatepolymerization route. Alternatively, in other instances, partiallycuring the ink comprises cyclopolymerizing the cyclopolymerizablemonomer. In some cases, partially curing the ink primarily comprisessuch cyclopolymerization of the cyclopolymerizable monomer.

Further, in some embodiments, a post-curing is performed after partiallycuring is performed. For example, in some cases, post-curing is carriedout after selectively depositing all layers of the ink necessary to forma desired 3D article, after partially curing all layers of the ink, orafter both of the foregoing steps have been performed. Moreover, in someembodiments, post-curing comprises photocuring. Any electromagneticradiation source not inconsistent with the objectives of the presentdisclosure may be used for a post-curing step described herein. Forexample, in some embodiments, the electromagnetic radiation source canbe a light source that has a higher energy, a lower energy, or the sameenergy as the electromagnetic radiation source used for partial curing.In some cases wherein the electromagnetic radiation source used forpost-curing has a higher energy (i.e., a shorter wavelength) than thatused for partial curing, a Xe arc lamp can be used for partial curingand a Hg lamp can be used for post-curing.

Additionally, in some instances, post-curing of deposited layers of anink described herein includes cyclopolymerizing the first ethenyl orethynyl moiety and the second ethenyl or ethynyl moiety of thecyclopolymerizable monomer of the ink. In some cases, post-curingprimarily includes such cyclopolymerization. For example, in someembodiments, more than 50%, more than 60%, or more than 70% of thepolymerization, during post-curing, occurs via cyclopolymerizationrather than by some other route, e.g., via (meth)acrylatepolymerization. During post-curing, some or none of the polymerizationmay occur via a route other than cyclopolymerization described herein.Alternatively, in other instances, post-curing includes (meth)acrylatepolymerization, such as that described above for the partially curingstep. In some embodiments, post-curing may even include such(meth)acrylate polymerization as the primary polymerization or curing ofthe post-curing step.

Additionally, after post-curing, in some cases, the deposited layers ofink are at least about 80% polymerized or cross-linked or at least about85% polymerized or cross-linked. In some embodiments, the depositedlayers of ink are at least about 90%, at least about 95%, at least about98%, or at least about 99% polymerized or cross-linked. In someinstances, the deposited layers of ink are bout 80-100%, about 80-99%,about 80-95%, about 85-100%, about 85-99%, about 85-95%, about 90-100%,or about 90-99% polymerized or cross-linked.

B. Vat Polymerization Methods

It is also possible to form a 3D article from an ink described hereinusing a vat polymerization method, such as an SLA method. Thus, in somecases, a method of printing a 3D article described herein comprisesretaining an ink described herein in a fluid state in a container andselectively applying energy to the ink in the container to solidify atleast a portion of a fluid layer of the ink, thereby forming asolidified layer that defines a cross-section of the 3D article.Additionally, a method described herein can further comprise raising orlowering the solidified layer of ink to provide a new or second fluidlayer of unsolidified ink at the surface of the fluid ink in thecontainer, followed by again selectively applying energy to the ink inthe container to solidify at least a portion of the new or second fluidlayer of the ink to form a second solidified layer that defines a secondcross-section of the 3D article. Further, the first and secondcross-sections of the 3D article can be bonded or adhered to one anotherin the z-direction (or build direction corresponding to the direction ofraising or lowering recited above) by the application of the energy forsolidifying the ink. Moreover, selectively applying energy to the ink inthe container can comprise applying electromagnetic radiation having asufficient energy to cure the ink. In some instances, theelectromagnetic radiation has an average wavelength of 300-900 nm, andin other embodiments the electromagnetic radiation has an averagewavelength that is less than 300 nm. In some cases, the curing radiationis provided by a computer controlled laser beam. In addition, in somecases, raising or lowering a solidified layer of ink is carried outusing an elevator platform disposed in the container of fluid ink. Amethod described herein can also comprise planarizing a new layer offluid ink provided by raising or lowering an elevator platform. Suchplanarization can be carried out, in some cases, by a wiper or roller.

It is further to be understood that the foregoing process can berepeated a desired number of times to provide the 3D article. Forexample, in some cases, this process can be repeated “n” number oftimes, wherein n can be up to about 100,000, up to about 50,000, up toabout 10,000, up to about 5000, up to about 1000, or up to about 500.Thus, in some embodiments, a method of printing a 3D article describedherein can comprise selectively applying energy to an ink in a containerto solidify at least a portion of an nth fluid layer of the ink, therebyforming an nth solidified layer that defines an nth cross-section of the3D article, raising or lowering the nth solidified layer of ink toprovide an (n+1)th layer of unsolidified ink at the surface of the fluidink in the container, selectively applying energy to the (n+1)th layerof ink in the container to solidify at least a portion of the (n+1)thlayer of the ink to form an (n+1)th solidified layer that defines an(n+1)th cross-section of the 3D article, raising or lowering the (n+1)thsolidified layer of ink to provide an (n+2)th layer of unsolidified inkat the surface of the fluid ink in the container, and continuing torepeat the foregoing steps to form the 3D article. Further, it is to beunderstood that one or more steps of a method described herein, such asa step of selectively applying energy to a layer of ink, can be carriedout according to an image of the 3D article in a computer-readableformat. General methods of 3D printing using stereolithography arefurther described, inter alia, in U.S. Pat. Nos. 5,904,889 and6,558,606.

Performing a printing process described above can provide a printed 3Darticle from an ink described herein that has a high feature resolution.The “feature resolution” of an article, for reference purposes herein,can be the smallest controllable physical feature size of the article.The feature resolution of an article can be described in terms of a unitof distance such as microns (μm), or in terms of dots per inch (dpi). Asunderstood by one of ordinary skill in the art, a higher featureresolution corresponds to a higher dpi value but a lower distance valuein μm. In some cases, an article formed by depositing or solidifying anink described herein can have a feature resolution of about 500 μm orless, about 200 μm or less, about 100 μm or less, or about 50 μm orless, including at elevated temperatures. In some embodiments, anarticle has a feature resolution between about 50 μm and about 500 μm,between about 50 μm and about 200 μm, between about 50 μm and about 100μm, or between about 100 μm and about 200 μm. Correspondingly, in someinstances, an article described herein has a feature resolution of atleast about 100 dpi, at least about 200 dpi, at least about 250 dpi, atleast about 400 dpi, or at least about 500 dpi. In some cases, thefeature resolution of an article is between about 100 dpi and about 600dpi, between about 100 dpi and about 250 dpi, or between about 200 dpiand about 600 dpi.

In a vat polymerization method such as described above, the ink may bepartially cured as described in Section IIA above. For example, in someembodiments, selectively applying energy to the ink in the container tosolidify at least a portion of a fluid layer of the ink may includepartially curing at least a portion of a fluid layer of the ink. Inother embodiments, partial curing of at least a portion of a fluid layerof the ink may occur after a first layer of the ink is provided andsolidified, before or after a second layer of the ink is provided orsolidified, or before or after one, several, or all subsequent layers ofthe ink are provided or solidified.

Additionally, in some embodiments of a vat polymerization methoddescribed herein, after partial curing or after the desired 3D articleis formed, post-curing as described in Section IIA above may beperformed. The desired 3D article may be, for example, an article thatcorresponds to the design in a CAD file.

III. Printed 3D Articles

In another aspect, printed 3D articles are described herein. In someembodiments, a printed 3D article is formed from an ink describedherein. Any ink described hereinabove in Section I may be used. Forexample, in some cases, the ink comprises 10-70 or 20-40 wt. % of acyclopolymerizable monomer as described in Section I above, based on thetotal weight of the ink. Further, in some embodiments, the ink has adynamic viscosity, prior to curing, of 1,600 cP or less or 500 cP orless at 30° C. Moreover, in some cases, a printed 3D article describedherein, when cured (e.g., when post-cured), can exhibit mechanicalproperties similar to injection-molded thermoplastic articles. Forexample, such a printed 3D article can exhibit, in some cases, anelongation at break of about 10 to 70%, about 10 to 60%, about 15 to50%, or about 20 to 50%, when measured according to ASTM D638. Further,a printed 3D article described herein, in some cases, can have a tensilestrength of about 40 to 70 MPa about 40 to 60 MPa, or about 45 to 55 MPawhen measured according to ASTM D638. Additionally, a printed 3D articledescribed herein, in some embodiments, can have a tensile modulus ofabout 1800 to 2100 MPa, about 1900 to 2100 MPa, or about 1950 to 2050MPa when measured according to ASTM D638. Notably, a printed 3D articledescribed herein may have an impact resistance (Notched) of 1 to 4ft·lb/in (Notched), 1 to 3 ft·lb/in (Notched), or 1 to 2 ft·lb/in(Notched) when measured according to ASTM D256. Finally, a printed 3Darticle described herein may have a flexual modulus of 2000 to 2500 MPa,2100 to 2400 MPa, or 2100 to 2200 MPa when measured according to ASTMD790.

IV. Cyclopolymerizable Compounds

In another aspect, cyclopolymerizable compounds are described herein.Such compounds can be used as monomers in inks for 3D printing, asdescribed in Sections I, II, and III above. However, it is further to beunderstood that novel cyclopolymerizable compounds described herein mayalso be used for applications other than 3D printing applications. Forinstances, in some embodiments, a cyclopolymerizable compound describedherein can be used to form a curable coating such as a UV-curablecoating.

In some cases, a cyclopolymerizable compound described herein has thestructure of Formula (I) from Section I hereinabove:

For example, in some embodiments, a cyclopolymerizable compounddescribed herein has the structure of Formula (I), wherein R₅ is:

wherein R₆ is as defined above.

Exemplary compounds of this types include the following:

In other instances, a cyclopolymerizable compound described herein hasthe structure of Formula (I), wherein R₅ is:

Non-limiting examples of compounds of this type include the following:

In still other cases, a cyclopolymerizable compound described herein hasthe structure of Formula (I), wherein R₅ is:

Exemplary compounds of this type include

In other cases, a compound described herein has the structure of Formula(I), wherein R₅ is:

In some embodiments, such a compound is

In still other cases, a cyclopolymerizable compound described herein hasthe structure of Formula (II) from Section I hereinabove:

In some such instances, for example, the compound is

Additional embodiments of cyclopolymerizable compounds described hereinare provided in the specific Examples hereinbelow. It is to beunderstood that further embodiments of cyclopolymerizable compounds,which may not be specifically described below, can be prepared in amanner analogous to the synthetic protocols of the Examples.

Some embodiments of inks for 3D printing are also further illustrated inthe following non-limiting Examples.

Example 1 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet are added 46.7grams of phenol chloroformate (MW 156.5) and 100 grams oftetrahydrofuran (THF). The vessel is then placed in a largecrystallizing dish with ice/water/salt and stirring is begun to cool themixture to about 0° C. To a different 400 mL beaker are added 31.0 gramsof triethyl amine (TEA) (MW=101), 100 grams of THF, and 28.9 grams ofdiallylamine (DAA) (MW=97). This mixture is stirred with a stir roduntil a homogeneous composition is obtained. The mixture of TEA/DAA/THFis slowly pipetted dropwise over about 1 hour to the cooled phenolchloroformate/THF. A white precipitate forms almost instantly, sometimesviolently reacting during the initial 50 mL addition of TEA/DAA/THF. Ifthe contents of the reaction mixture in the 1 liter vessel get too thickfor the magnet to stir, additional increments (of about 25 mL) of THFare added to thin the mixture and allow stirring to continue. If thecontents still get too thick, the 1 liter vessel is manually stirredwith a large glass stir rod until all the TEA/DAA/THF has been added.The reaction mixture is allowed to stir, coming to room temperature,overnight.

The next day, a 2 liter vacuum flask equipped with a 400 mL Buchnerfunnel are set up. A 110 mm Whatman 41 filter is added to the funnel andwetted with acetone and the contents of the 1 liter vessel (containingthe product with the TEA-HCl salt in THF) is poured through the Buchnerfunnel, with vacuum on. The TEA-HCl salt is collected on the filter andthe filtrate, containing the product in THF, is collected in the vacuumflask.

A 60 mL disposable syringe is fitted with a 1 μm glass microfilter, witha plug of glass wool added to the bottom, 0.5 inches of sand and about35 mL of silica gel added. This is placed on a clean 2 L vacuum flaskwith adaptor. About 35 mL of acetone is added and allowed to wet thesilica gel. The product mixture is then slowly added to the syringe andthe vacuum introduced. The 1 liter of the product/salt/THF is quicklypoured into syringe and filtered over the course of about 5 minutes. Thefiltrate, containing the product and THF/acetone, is then added to a 2liter clean and dry beaker and allowed to evaporate, assisted by agentle nitrogen flow overnight. The product is added to a pre-weighedjar and capped. In this manner, 59.9 g of product was obtained,resulting in a 92.4% yield. A Fourier transform infrared (FTIR) spectrumwas obtained to qualitatively verify the product based on the carbonylC═O position.

Example 2 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet are added 51.8grams of 2-ethylhexyl chloroformate (MW 192.5) and 200 grams oftetrahydrofuran (THF). The vessel is then placed in a largecrystallizing dish with ice/water/salt and stirring is begun to cool themixture to about 0° C. To a different 400 mL beaker are added 28.0 gramsof triethyl amine (TEA) (MW=101), 100 grams of THF, and 26.2 grams ofdiallylamine (DAA) (MW=97). This mixture is stirred with a stir roduntil a homogeneous composition is obtained. The mixture of TEA/DAA/THFis slowly pipetted dropwise over about 1 hour to the cooled 2-ethylhexylchloroformate/THF. A white precipitate forms almost instantly, sometimesviolently reacting during the initial 50 mL addition of TEA/DAA/THF. Ifthe contents of the reaction mixture in the 1 liter vessel get too thickfor the magnet to stir, additional increments (of about 25 mL) of THFare added to thin the mixture and allow stirring to continue. If thecontents still get too thick, the 1 liter vessel is manually stirredwith a large glass stir rod until all the TEA/DAA/THF has been added.The reaction mixture is allowed to stir, coming to room temperature,overnight.

The next day, a 2 liter vacuum flask equipped with a 400 mL Buchnerfunnel are set up. A 110 mm Whatman 41 filter is added to the funnel andwetted with acetone and the contents of the 1 liter vessel (containingthe product with the TEA-HCl salt in THF) is poured through the Buchnerfunnel, with vacuum on. The TEA-HCl salt is collected on the filter andthe filtrate, containing the product in THF, is collected in the vacuumflask.

A 60 mL disposable syringe is fitted with a 1 μm glass microfilter, witha plug of glass wool added to the bottom, 0.5 inches of sand and about35 mL of silica gel added. This is placed on a clean 2 L vacuum flaskwith adaptor. About 35 mL of acetone is added and allowed to wet thesilica gel. The product mixture is then slowly added to the syringe andthe vacuum introduced. The 1 liter of the product/salt/THF is quicklypoured into syringe and filtered over the course of about 5 minutes. Thefiltrate, containing the product and THF/acetone, is then added to a 2liter clean and dry beaker and allowed to evaporate, assisted by agentle nitrogen flow overnight. The product is added to a pre-weighedjar and capped. In this manner, 65.8 g of product was obtained,resulting in a 96.4% yield. A Fourier transform infrared (FTIR) spectrumwas obtained to qualitatively verify the product based on the carbonylC═O position.

Example 3 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet are added 58.5grams of 2-ethylhexoyl chloride (MW 163) and 150 grams oftetrahydrofuran (THF). The vessel is then placed in a largecrystallizing dish with ice/water/salt and stirring is begun to cool themixture to about 0° C. To a different 400 mL beaker are added 36.2 gramsof triethyl amine (TEA) (MW=101), 100 grams of THF, and 34.8 grams ofdiallylamine (DAA) (MW=97). This mixture is stirred with a stir roduntil a homogeneous composition is obtained. The mixture of TEA/DAA/THFis slowly pipetted dropwise over about 1 hour to the cooled2-ethylhexoyl chloride/THF. A white precipitate forms almost instantly,sometimes violently reacting during the initial 50 mL addition ofTEA/DAA/THF. If the contents of the reaction mixture in the 1 litervessel get too thick for the magnet to stir, additional increments (ofabout 25 mL) of THF are added to thin the mixture and allow stirring tocontinue. If the contents still get too thick, the 1 liter vessel ismanually stirred with a large glass stir rod until all the TEA/DAA/THFhas been added. The reaction mixture is allowed to stir, coming to roomtemperature, overnight.

The next day, a 2 liter vacuum flask equipped with a 400 mL Buchnerfunnel are set up. A 110 mm Whatman 41 filter is added to the funnel andwetted with acetone and the contents of the 1 liter vessel (containingthe product with the TEA-HCl salt in THF) is poured through the Buchnerfunnel, with vacuum on. The TEA-HCl salt is collected on the filter andthe filtrate, containing the product in THF, is collected in the vacuumflask.

A 60 mL disposable syringe is fitted with a 1 μm glass microfilter, witha plug of glass wool added to the bottom, 0.5 inches of sand and about35 mL of silica gel added. This is placed on a clean 2 L vacuum flaskwith adaptor. About 35 mL of acetone is added and allowed to wet thesilica gel. The product mixture is then slowly added to the syringe andthe vacuum introduced. The 1 liter of the product/salt/THF is quicklypoured into syringe and filtered over the course of about 5 minutes. Thefiltrate, containing the product and THF/acetone, is then added to a 2liter clean and dry beaker and allowed to evaporate, assisted by agentle nitrogen flow overnight. The product is added to a pre-weighedjar and capped. In this manner, 77.0 g of product was obtained,resulting in a 96.3% yield. A Fourier transform infrared (FTIR) spectrumwas obtained to qualitatively verify the product based on the carbonylC═O position.

Example 4 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet are added 35.1grams of benzoyl chloride (MW 140.5) and 150 grams of tetrahydrofuran(THF). The vessel is then placed in a large crystallizing dish withice/water/salt and stirring is begun to cool the mixture to about 0° C.To a different 400 mL beaker are added 26 grams of triethyl amine (TEA)(MW=101), 100 grams of THF, and 24.2 grams of diallylamine (DAA)(MW=97). This mixture is stirred with a stir rod until a homogeneouscomposition is obtained. The mixture of TEA/DAA/THF is slowly pipetteddropwise over about 1 hour to the cooled benzoyl chloride/THF. A whiteprecipitate forms almost instantly, sometimes violently reacting duringthe initial 50 mL addition of TEA/DAA/THF. If the contents of thereaction mixture in the 1 liter vessel get too thick for the magnet tostir, additional increments (of about 25 mL) of THF are added to thinthe mixture and allow stirring to continue. If the contents still gettoo thick, the 1 liter vessel is manually stirred with a large glassstir rod until all the TEA/DAA/THF has been added. The reaction mixtureis allowed to stir, coming to room temperature, overnight.

The next day, a 2 liter vacuum flask equipped with a 400 mL Buchnerfunnel are set up. A 110 mm Whatman 41 filter is added to the funnel andwetted with acetone and the contents of the 1 liter vessel (containingthe product with the TEA-HCl salt in THF) is poured through the Buchnerfunnel, with vacuum on. The TEA-HCl salt is collected on the filter andthe filtrate, containing the product in THF, is collected in the vacuumflask.

A 60 mL disposable syringe is fitted with a 1 μm glass microfilter, witha plug of glass wool added to the bottom, 0.5 inches of sand and about35 mL of silica gel added. This is placed on a clean 2 L vacuum flaskwith adaptor. About 35 mL of acetone is added and allowed to wet thesilica gel. The product mixture is then slowly added to the syringe andthe vacuum introduced. The 1 liter of the product/salt/THF is quicklypoured into syringe and filtered over the course of about 5 minutes. Thefiltrate, containing the product and THF/acetone, is then added to a 2liter clean and dry beaker and allowed to evaporate, assisted by agentle nitrogen flow overnight. The product is added to a pre-weighedjar and capped. In this manner, 49.6 g of product was obtained,resulting in a 98.8% yield. A Fourier transform infrared (FTIR) spectrumwas obtained to qualitatively verify the product based on the carbonylC═O position.

Example 5 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet are added 102grams of isobutyl chloroformate (MW 140.5) and 200 grams oftetrahydrofuran (THF). The vessel is then placed in a largecrystallizing dish with ice/water/salt and stirring is begun to cool themixture to about 0° C. To a different 400 mL beaker are added 76.0 gramsof triethyl amine (TEA) (MW=101), 100 grams of THF, and 72.5 grams ofdiallylamine (DAA) (MW=97). This mixture is stirred with a stir roduntil a homogeneous composition is obtained. The mixture of TEA/DAA/THFis slowly pipetted dropwise over about 1 hour to the cooled isobutylchloroformate/THF. A white precipitate forms almost instantly, sometimesviolently reacting during the initial 50 mL addition of TEA/DAA/THF. Ifthe contents of the reaction mixture in the 1 liter vessel get too thickfor the magnet to stir, additional increments (of about 25 mL) of THFare added to thin the mixture and allow stirring to continue. If thecontents still get too thick, the 1 liter vessel is manually stirredwith a large glass stir rod until all the TEA/DAA/THF has been added.The reaction mixture is allowed to stir, coming to room temperature,overnight.

The next day, a 2 liter vacuum flask equipped with a 400 mL Buchnerfunnel are set up. A 110 mm Whatman 41 filter is added to the funnel andwetted with acetone and the contents of the 1 liter vessel (containingthe product with the TEA-HCl salt in THF) is poured through the Buchnerfunnel, with vacuum on. The TEA-HCl salt is collected on the filter andthe filtrate, containing the product in THF, is collected in the vacuumflask.

A 60 mL disposable syringe is fitted with a 1 μm glass microfilter, witha plug of glass wool added to the bottom, 0.5 inches of sand and about35 mL of silica gel added. This is placed on a clean 2 L vacuum flaskwith adaptor. About 35 mL of acetone is added and allowed to wet thesilica gel. The product mixture is then slowly added to the syringe andthe vacuum introduced. The 1 liter of the product/salt/THF is quicklypoured into syringe and filtered over the course of about 5 minutes. Thefiltrate, containing the product and THF/acetone, is then added to a 2liter clean and dry beaker and allowed to evaporate, assisted by agentle nitrogen flow overnight. The product is added to a pre-weighedjar and capped. In this manner, 139.2 g of product was obtained,resulting in a 94.6% yield. A Fourier transform infrared (FTIR) spectrumwas obtained to qualitatively verify the product based on the carbonylC═O position.

Example 6 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet are added 52.6grams of acetyl chloride (MW 78.5) and 300 grams of tetrahydrofuran(THF). The vessel is then placed in a large crystallizing dish withice/water/salt and stirring is begun to cool the mixture to about 0° C.To a different 400 mL beaker are added 68 grams of triethyl amine (TEA)(MW=101), 100 grams of THF, and 65 grams of diallylamine (DAA) (MW=97).This mixture is stirred with a stir rod until a homogeneous compositionis obtained. The mixture of TEA/DAA/THF is slowly pipetted dropwise overabout 1 hour to the cooled acetyl chloride/THF. A white precipitateforms almost instantly, sometimes violently reacting during the initial50 mL addition of TEA/DAA/THF. If the contents of the reaction mixturein the 1 liter vessel get too thick for the magnet to stir, additionalincrements (of about 25 mL) of THF are added to thin the mixture andallow stirring to continue. If the contents still get too thick, the 1liter vessel is manually stirred with a large glass stir rod until allthe TEA/DAA/THF has been added. The reaction mixture is allowed to stir,coming to room temperature, overnight.

The next day, a 2 liter vacuum flask equipped with a 400 mL Buchnerfunnel are set up. A 110 mm Whatman 41 filter is added to the funnel andwetted with acetone and the contents of the 1 liter vessel (containingthe product with the TEA-HCl salt in THF) is poured through the Buchnerfunnel, with vacuum on. The TEA-HCl salt is collected on the filter andthe filtrate, containing the product in THF, is collected in the vacuumflask.

A 60 mL disposable syringe is fitted with a 1 μm glass microfilter, witha plug of glass wool added to the bottom, 0.5 inches of sand and about35 mL of silica gel added. This is placed on a clean 2 L vacuum flaskwith adaptor. About 35 mL of acetone is added and allowed to wet thesilica gel. The product mixture is then slowly added to the syringe andthe vacuum introduced. The 1 liter of the product/salt/THF is quicklypoured into syringe and filtered over the course of about 5 minutes. Thefiltrate, containing the product and THF/acetone, is then added to a 2liter clean and dry beaker and allowed to evaporate, assisted by agentle nitrogen flow overnight. The product is added to a pre-weighedjar and capped. In this manner, 83.7 g of product was obtained,resulting in a 83.7% yield. A Fourier transform infrared (FTIR) spectrumwas obtained to qualitatively verify the product based on the carbonylC═O position.

Example 7 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet are added 52.6grams of benzene sulfonylchloride (MW 176.5) and 200 grams oftetrahydrofuran (THF). The vessel is then placed in a largecrystallizing dish with ice/water/salt and stirring is begun to cool themixture to about 0° C. To a different 400 mL beaker are added 51 gramsof triethyl amine (TEA) (MW=101), 100 grams of THF, and 48.5 grams ofdiallylamine (DAA) (MW=97). This mixture is stirred with a stir roduntil a homogeneous composition is obtained. The mixture of TEA/DAA/THFis slowly pipetted dropwise over about 1 hour to the cooled benzenesulfonylchloride/THF. A white precipitate forms almost instantly,sometimes violently reacting during the initial 50 mL addition ofTEA/DAA/THF. If the contents of the reaction mixture in the 1 litervessel get too thick for the magnet to stir, additional increments (ofabout 25 mL) of THF are added to thin the mixture and allow stirring tocontinue. If the contents still get too thick, the 1 liter vessel ismanually stirred with a large glass stir rod until all the TEA/DAA/THFhas been added. The reaction mixture is allowed to stir, coming to roomtemperature, overnight.

The next day, a 2 liter vacuum flask equipped with a 400 mL Buchnerfunnel are set up. A 110 mm Whatman 41 filter is added to the funnel andwetted with acetone and the contents of the 1 liter vessel (containingthe product with the TEA-HCl salt in THF) is poured through the Buchnerfunnel, with vacuum on. The TEA-HCl salt is collected on the filter andthe filtrate, containing the product in THF, is collected in the vacuumflask.

A 60 mL disposable syringe is fitted with a 1 μm glass microfilter, witha plug of glass wool added to the bottom, 0.5 inches of sand and about35 mL of silica gel added. This is placed on a clean 2 L vacuum flaskwith adaptor. About 35 mL of acetone is added and allowed to wet thesilica gel. The product mixture is then slowly added to the syringe andthe vacuum introduced. The 1 liter of the product/salt/THF is quicklypoured into syringe and filtered over the course of about 5 minutes. Thefiltrate, containing the product and THF/acetone, is then added to a 2liter clean and dry beaker and allowed to evaporate, assisted by agentle nitrogen flow overnight. The product is added to a pre-weighedjar and capped. In this manner, 108 g of product was obtained, resultingin a 91.1% yield. A Fourier transform infrared (FTIR) spectrum wasobtained to qualitatively verify the product based on the carbonyl C═Oposition.

Example 8 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet are added 134.4grams of methane sulfonylchloride (MW 114.5) and 200 grams oftetrahydrofuran (THF). The vessel is then placed in a largecrystallizing dish with ice/water/salt and stirring is begun to cool themixture to about 0° C. To a different 400 mL beaker are added 120 gramsof triethyl amine (TEA) (MW=101), 100 grams of THF, and 113.9 grams ofdiallylamine (DAA) (MW=97). This mixture is stirred with a stir roduntil a homogeneous composition is obtained. The mixture of TEA/DAA/THFis slowly pipetted dropwise over about 1 hour to the cooled methanesulfonylchloride/THF. A white precipitate forms almost instantly,sometimes violently reacting during the initial 50 mL addition ofTEA/DAA/THF. If the contents of the reaction mixture in the 1 litervessel get too thick for the magnet to stir, additional increments (ofabout 25 mL) of THF are added to thin the mixture and allow stirring tocontinue. If the contents still get too thick, the 1 liter vessel ismanually stirred with a large glass stir rod until all the TEA/DAA/THFhas been added. The reaction mixture is allowed to stir, coming to roomtemperature, overnight.

The next day, a 2 liter vacuum flask equipped with a 400 mL Buchnerfunnel are set up. A 110 mm Whatman 41 filter is added to the funnel andwetted with acetone and the contents of the 1 liter vessel (containingthe product with the TEA-HCl salt in THF) is poured through the Buchnerfunnel, with vacuum on. The TEA-HCl salt is collected on the filter andthe filtrate, containing the product in THF, is collected in the vacuumflask.

A 60 mL disposable syringe is fitted with a 1 μm glass microfilter, witha plug of glass wool added to the bottom, 0.5 inches of sand and about35 mL of silica gel added. This is placed on a clean 2 L vacuum flaskwith adaptor. About 35 mL of acetone is added and allowed to wet thesilica gel. The product mixture is then slowly added to the syringe andthe vacuum introduced. The 1 liter of the product/salt/THF is quicklypoured into syringe and filtered over the course of about 5 minutes. Thefiltrate, containing the product and THF/acetone, is then added to a 2liter clean and dry beaker and allowed to evaporate, assisted by agentle nitrogen flow overnight. The product is added to a pre-weighedjar and capped. In this manner, 204 g of product was obtained, resultingin a 95.3% yield. A Fourier transform infrared (FTIR) spectrum wasobtained to qualitatively verify the product based on the carbonyl C═Oposition.

Example 9 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet is added 155grams of isocyanatoethylmethacrylate (IEM) (MW 155). The vessel is thenplaced in a large crystallizing dish with ice/water, and stirring isbegun to cool the mixture to about 0° C. About 97 grams of diallylamine(DAA) (MW=97) is added dropwise over about 1 hour to the cooled IEM. Thereaction mixture is allowed to stir, coming to room temperature,overnight. The next day an IR was taken of the reaction product toverify that no excess isocyanate remained (by the lack of a peak at˜2230 cm⁻¹). Dry air is bubbled subsurface overnight to ensure no excessdiallylamine exists in the reaction product.

Example 10 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet is added 143grams of isocyanatoethylacrylate (IEA) (MW 143). The vessel is thenplaced in a large crystallizing dish with ice/water, and stirring isbegun to cool the mixture to about 0° C. About 97 grams of diallylamine(DAA) (MW=97) is added dropwise over about 1 hour to the cooled IEA. Thereaction mixture is allowed to stir, coming to room temperature,overnight. The next day an IR was taken of the reaction product toverify that no excess isocyanate remained (by the lack of a peak at˜2230 cm⁻¹). Dry air is bubbled subsurface overnight to ensure no excessdiallylamine exists in the reaction product.

Example 11 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet is added 50 gramsof trimethyhexamethylenediisocyante (TMHDI) (MW 210). The vessel is thenplaced in a large crystallizing dish with ice/water, and stirring isbegun to cool the mixture to about 0° C. About 46 grams of diallylamine(DAA) (MW=97) is added dropwise over about 1 hour to the cooled TMHDI.The reaction mixture is allowed to stir, coming to room temperature,overnight. The next day an IR was taken of the reaction product toverify that no excess isocyanate remained (by the lack of a peak at˜2230 cm⁻¹). Dry air is bubbled subsurface overnight to ensure no excessdiallylamine exists in the reaction product.

Example 12 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet is added 20.0grams of nadic anhydride (MW 178). The vessel is then placed in a largecrystallizing dish with ice/water, and stirring is begun to cool themixture to about 0° C. About 10.8 grams of diallylamine (DAA) (MW=97) isadded dropwise over about 1 hour to the cooled nadic anhydride. Thereaction mixture is allowed to stir, coming to room temperature,overnight. Dry air is bubbled subsurface to the reaction product (aviscous liquid) overnight to ensure no excess diallylamine exists in thereaction product.

Example 13 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet is added 40.0grams of octenylsuccinic anhydride (OSA) (MW 210). The vessel is thenplaced in a large crystallizing dish with ice/water, and stirring isbegun to cool the mixture to about 0° C. About 18.5 grams ofdiallylamine (DAA) (MW=97) is added dropwise over about 1 hour to thecooled OSA. The reaction mixture is allowed to stir, coming to roomtemperature, overnight. Dry air is bubbled subsurface to the reactionproduct (a viscous liquid) overnight to ensure no excess diallylamineexists in the reaction product.

Example 14 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet is added 53.5grams of m-tolyl isocyanate (MW 232). The vessel is then placed in alarge crystallizing dish with ice/water, and stirring is begun to coolthe mixture to about 0° C. About 39 grams of diallylamine (DAA) (MW=97)is added dropwise over about 1 hour to the cooled m-tolyl isocyanate.The reaction mixture is allowed to stir, coming to room temperature,overnight. The next day an IR was taken of the reaction product toverify that no excess isocyanate remained (by the lack of a peak at˜2230 cm⁻¹). Dry air is bubbled subsurface overnight to ensure no excessdiallylamine exists in the reaction product.

Example 15 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet is added 202.5grams of 3-chlorophenylisocyanate (MW 153.5). The vessel is then placedin a large crystallizing dish with ice/water, and stirring is begun tocool the mixture to about 0° C. About 128 grams of diallylamine (DAA)(MW=97) is added dropwise over about 1 hour to the cooled3-chlorophenylisocyanate. The reaction mixture is allowed to stir,coming to room temperature, overnight. The next day an IR was taken ofthe reaction product to verify that no excess isocyanate remained (bythe lack of a peak at ˜2230 cm⁻¹). Dry air is bubbled subsurfaceovernight to ensure no excess diallylamine exists in the reactionproduct.

Example 16 Cyclopolymerizable Compound

A cyclopolymerizable compound having the following structure wasprepared as described below.

To a 1 liter vessel with a large TEFLON® coated magnet is added 100.5grams of isoprenyl dimethylbenzylisocyanate (TMI-meta) (MW 201). Thevessel is then placed in a large crystallizing dish with ice/water, andstirring is begun to cool the mixture to about 0° C. About 48.5 grams ofdiallylamine (DAA) (MW=97) is added dropwise over about 1 hour to thecooled TMI-meta. The reaction mixture is allowed to stir, coming to roomtemperature, overnight. The next day an IR was taken of the reactionproduct to verify that no excess isocyanate remained (by the lack of apeak at ˜2230 cm⁻¹). Dry air is bubbled subsurface overnight to ensureno excess diallylamine exists in the reaction product.

Example 17 Cyclopolymerizable Compound

A cyclopolymerizable compound having the structure of Formula (II) isprepared according to the reaction scheme illustrated in FIG. 3. Withreference to FIG. 3, diallylamine and a diisocyanate (2 equivalentseach) are reacted with a polyol (of the poly(ethylene glycol) type) (1equivalent) in two steps. In Step (1), the polyol reacts with thediisocyanate to form a poly(ethylene glycol) “capped” with isocyanatemoieties or functional groups at both ends. This species then reacts, inStep (2), with diallylamine to form the final product having thestructure of Formula (II). In this manner, a “dimer” ofcyclopolymerizable monomers is formed.

As described above, it is to be understood that other cyclopolymerizablemonomers can be formed in an analogous manner, as understood by one ofordinary skill in the art.

Example 18 Method of Preparing Inks

Inks according to some embodiments described herein were prepared asfollows. Specifically, to prepare a particular ink, the components ofthe particular ink were mixed in a reaction vessel, as shown in theTables below. The amounts of the various components in the Tables belowrefer to the wt. % of each component of the identified ink, based on thetotal weight of the ink. For each ink, the appropriate mixture washeated to a temperature of about 75° C.-85° C. with stirring. Theheating and stirring were continued until the mixture attained asubstantially homogenized molten state. The molten mixture was thenfiltered. Next, the filtered mixture was allowed to cool to ambienttemperature.

Example 19 Cyclopolymerizable Monomer Variants

Inks 1-6 in Table I below were prepared according to the procedure inExample 18. Inks 1-6 were prepared using different types ofcyclopolymerizable monomer. The cyclopolymerizable monomer for Ink I wasthe monomer of Example 1 above. For Ink 2, the cyclopolymerizablemonomer was the monomer of Example 9 above. For Ink 3, thecyclopolymerizable monomer was the monomer of Example 7 above. For Ink4, the cyclopolymerizable monomer was the monomer of Example 15 above.For Ink 5, the cyclopolymerizable monomer was the monomer of Example 6.For Ink 6, the cyclopolymerizable monomer was the monomer of Example 8.Selected properties of Inks 1-6, after curing, are provided in Table II.

In Table II, impact strength was measured according to ASTM D256.Tensile strength was measured according to ASTM D638. Percent elongationwas measured according to ASTM D638. Glass transition temperature (Tg)was measured by dynamic mechanical analysis (DMA) using the Tan DeltaPeak, according to ASTM E1640. Heat distortion (or deflection)temperature (HDT) was measured using DMA at 0.455 MPa according to ASTMD648. Curing of the inks was carried out by casting the specific inkformulation into the proper shape/dimensions mold for the respectiveASTM testing protocol. The inks were then cured with three Phoseon FE300LEDs (395 nm×5 W/cm²) with a 2.5 cm pitch. Curing was undertaken for 6minutes. The molds were then placed into a DYMAX 5000 Hg cure oven forpost-cure. The samples were post-cured for 30 minutes on each side andthen removed from the mold and submitted for thermo-mechanical testing.

As shown in Table II, various cyclopolymerizable monomers could be usedto obtain a desirable combination of properties, particularly a desiredcombination of elongation and impact strength. It is to be especiallynoted that Inks 3 and 6 differed only in the identity of thecyclopolymerizable monomer (for each ink, the oligomeric curablematerial was the same 4.5:1 combination (by weight) of hydrophobicurethane acrylate and multifunctional acrylate oligomer; the non-curablepolymer/oligomer was the same carboxyl-terminated butadiene andbutadiene-acrylonitrile copolymer (CTBN); and the photoinitiator was thesame 6:1 combination of Lucirin TPO and Speedcure 84).

TABLE I Ink Compositions (amounts in wt. %). Ink 1 Ink 2 Ink 3 Ink 4 Ink5 Ink 6 Cyclopolymerizable 31.86 47.99 31.57 47.92 31.8 31.8 MonomerAdditional 0 47.87 0 0 0 0 Monomeric Curable Material Oligomeric 57.71 058.69 47.92 58.1 58.2 Curable Material Photoinitiator 3.47 4.14 3.434.16 3.5 3.5 Colorant 0 0 0 0 0 0 Non-Curable 6.96 0 6.31 0 6.6 6.5Polymer/Oligomer

TABLE II Ink Properties. Ink 3 Ink 5 Ink 6 Impact Strength 67.5 112.656.6 (J/m) Tensile Strength 27.32 15.61 23.38 (MPa) % Elongation 48.9942.07 44.41 Tg (° C.) 74.2 — 71.7 HDT (° C.) 47.70 — 42.26

Example 20 Additional Example Inks

Additional inks according to the present disclosure were also prepared,using various components. Specifically, Inks 7-13 in Table III belowwere prepared according to the procedure in Example 18, using thecomponents identified in Tables IV and V. In Tables IV and V, thecyclopolymerizable monomer for each ink is identified with reference tothe specific Examples (“Ex.”) above. Also, for each of Inks 7-13, thephotoinitiator was an approximate 6:1 to 7:1 combination (by weight) ofLucirin TPO and Speedcure 84.

TABLE III Ink Compositions (amounts in wt. %). Ink 7 Ink 8 Ink 9 Ink 10Ink 11 Ink 12 Ink 13 Cyclopolymerizable 47.95 47.86 55.83 55.19 55.7356.7 30.0 Monomer Additional Monomeric 48.07 48.15 0 0 0 0 0 CurableMaterial Oligomeric 0 0 40.03 40.71 40.13 39.2 65.85 Curable MaterialPhotoinitiator 3.98 3.99 4.14 4.1 4.14 4.1 4.15 Colorant 0 0 0 0 0 0 0Non-Curable 0 0 0 0 0 0 0 Polymer/Oligomer

TABLE IV Ink Components. Ink 7 Ink 8 Ink 13 Cyclopolymerizable Ex. 7 Ex.8 Ex. 11 Monomer Additional IBOA IBOA — Monomeric Curable MaterialOligomeric — — 30:36 ratio Curable (by weight) of Material polyesterurethane acryalte and ethoxylated (10) bisphenol A diacrylate

TABLE V Ink Components. Ink 9 Ink 10 Ink 11 Ink 12 CyclopolymerizableEx. 1 Ex. 2 Ex. 3 Ex. 4 Monomer Oligomeric aliphatic aliphatic aliphaticaliphatic Curable polyether polyether polyether polyether Materialurethane urethane urethane urethane acrylate acrylate acrylate acrylate

Example 21 Comparative Data

Inks 3, 5, and 6 above were compared to Comparative (“Comp.”) Inks 1 and2 in Table VI below. All inks in Table VI were prepared according to theprocedure in Example 18. Unlike Inks 3, 5, and 6, each of ComparativeInks 1 and 2 lacks a cyclopolymerizable monomer within the range ofamounts described herein. Instead, the Comparative Inks include adifferent, non-cyclopolymerizable monomer. Comparative Ink 1 includesIBOA instead of a cyclopolymerizable monomer. Comparative Ink 2 includes2-phenoxyethyl acrylate instead of a cyclopolymerizable monomer.Comparative Inks 1 and 2 otherwise include similar amounts of the sameadditional components as Inks 3, 5, and 6 (e.g., the oligomeric curablematerial, photoinitiator, and non-curable polymer/oligomer are the samechemical species in substantially the same amounts in all of the inks inTable VI). As shown in Table VI, Inks 3, 5, and 6 exhibited acombination of relatively high impact strength and relatively highelongation at break (within ranges described hereinabove), as comparedto Comparative Ink 1 and Comparative Ink 2.

TABLE VI Ink Compositions (amounts in wt %). Comp. Comp. Ink 3 Ink 5 Ink6 Ink 1 Ink 2 Cyclopolymerizable Ex. 7 Ex. 6 Ex. 8 — — MonomerCyclopolymerizable 31.57 31.8 31.8 0 0 Monomer Amount Additional 0 0 032.02 31.96 Monomeric Curable Material Oligomeric 58.69 58.1 58.2 57.5857.69 Curable Material Photoinitiator 3.43 3.5 3.5 3.5 3.49 Colorant 0 00 0 0 Non-Curable 6.31 6.6 6.5 6.9 6.86 Polymer/Oligomer Impact Strength67.50 112.60 56.60 31.4 54.5 (MPa) Elongation at 48.99 42.07 44.41 15.7631.74 Break (%)

Example 22 Additional Exemplary Ink Compositions

In addition to Inks 1-13 above, other inks according to the presentdisclosure are provided using the amounts in Table VII below. Theamounts in Table VII refer to the wt. % of each component of theidentified ink, based on the total weight of the ink. Additionally, “PI”stands for “photoinitiator.”

TABLE VII Ink Components (amounts in wt. %). Additional MonomericOligomeric Cyclopolymerizable Curable Curable Stabilizer/ MonomerMaterial Material Inhibitor Colorant PI 10-70  0-70 10-70 0.01-1   0-20-5 10-60 10-60 10-60 0.1-2   0.1-2   0-5 20-70  0-60 20-70 0.01-2  0.1-1   0-5 20-70 20-70  0-50 0.01-2   0-2 0.5-5   20-60  0-40 20-700.01-0.2    0-0.5 1-5 20-50  0-40 30-70 0.01-0.1  0.1-1.5 1-5 20-5010-40 30-70 0.01-0.5  0-2 1-5 20-40  0-40 30-65 0.01-1     0-1.5 1-520-40 10-40 30-65 0.05-1.5  0.01-1   1-5 30-40  0-40 30-65 0.01-2    0-0.5 1-5 30-40 10-40 30-65 0.01-0.2  0.5-1.5 1-5

All patent documents referred to herein are incorporated by reference intheir entireties. Various embodiments of the invention have beendescribed in fulfillment of the various objectives of the invention. Itshould be recognized that these embodiments are merely illustrative ofthe principles of the present invention. Numerous modifications andadaptations thereof will be readily apparent to those skilled in the artwithout departing from the spirit and scope of the invention.

That which is claimed:
 1. An ink for use in a three-dimensional printingsystem comprising: 10-70 wt. % cyclopolymerizable monomer, based on thetotal weight of the ink; 10-60 wt. % oligomeric curable material, basedon total weight of the ink; and up to 80 wt. % additional monomericcurable material, based on the total weight of the ink; wherein thecyclopolymerizable monomer comprises a first ethenyl or ethynyl moietyand a second ethenyl or ethynyl moiety.
 2. The ink of claim 1, whereinthe cyclopolymerizable monomer is present in the ink in an amount of20-40 wt. %, based on the total weight of the ink.
 3. The ink of claim1, wherein the cyclopolymerizable monomer comprises at least onecyclopolymerizable diallyl amine moiety.
 4. The ink of claim 1, whereinthe α-carbon of the first ethenyl or ethynyl moiety and the α-carbon ofthe second ethenyl or ethynyl moiety have a 1,5-relationship.
 5. The inkof claim 1, wherein the α-carbon of the first ethenyl or ethynyl moietyand the α-carbon of the second ethenyl or ethynyl moiety have a1,6-relationship.
 6. The ink of claim 1, wherein the α-carbon of thefirst ethenyl or ethynyl moiety and the α-carbon of the second ethenylor ethynyl moiety have a 1,7-relationship.
 7. The ink of claim 1,wherein the α-carbon of the first ethenyl or ethynyl moiety and theα-carbon of the second ethenyl or ethynyl moiety have a1,8-relationship.
 8. The ink of claim 1, wherein the cyclopolymerizablemonomer has the structure of Formula (I):

wherein: R₁ is a hydrocarbon group having 1-4 carbon atoms; R₂ is ahydrocarbon group having 1-4 carbon atoms; the total number of carbonatoms of R₁ and R₂ does not exceed 5; R₃ is HC═CH₂ or C≡CH; R₄ is HC═CH₂or C≡CH; R₅ is

or a polymerizable moiety; and R₆ is a substituted or unsubstitutedhydrocarbon group having 1-30 carbon atoms.
 9. The ink of claim 7,wherein R₅ is selected from


10. The ink of claim 1, wherein the cyclopolymerizable monomer has thestructure of Formula (II):

wherein: R₁ is a hydrocarbon group having 1-4 carbon atoms; R₂ is ahydrocarbon group having 1-4 carbon atoms; the total number of carbonatoms of R₁ and R₂ does not exceed 5; R₃ is HC═CH₂ or C≡CH; R₄ is HC═CH₂or C≡CH; R₇ is a hydrocarbon group having 1-4 carbon atoms; R₈ is ahydrocarbon group having 1-4 carbon atoms; the total number of carbonatoms of R₇ and R₈ does not exceed 5; R₉ is HC═CH₂ or C≡CH; R₁₀ isHC═CH₂ or C≡CH; and R₅ is a hydrocarbon group having 1-30 carbon atomsor a poly(alkylene glycol) having 2-30 alkylene glycol repeating units.11. The ink of claim 1 further comprising at least one photoinitiator.12. The ink of claim 1 further comprising at least one colorant and/orone or more additives selected from the group consisting of inhibitorsand stabilizing agents.
 13. The ink of claim 1, wherein the viscosity ofthe ink is 500 cP or less at 30° C.
 14. A method of printing athree-dimensional article comprising: selectively depositing layers ofan ink in a fluid state onto a substrate to form the three-dimensionalarticle, wherein the ink comprises the ink of claim
 1. 15. The method ofclaim 14 further comprising partially curing the ink prior to completionof deposition of all layers of the ink, wherein partially curing the inkprimarily comprises (meth)acrylate polymerization.
 16. The method ofclaim 15 further comprising post-curing the ink following completion ofdeposition of all layers of the ink, wherein post-curing the inkprimarily comprises cyclopolymerizing the cyclopolymerizable monomer.17. A method of printing a three-dimensional article comprising:retaining an ink in a fluid state in a container; selectively applyingenergy to the ink in the container to solidify at least a portion of afirst fluid layer of the ink, thereby forming a first solidified layerthat defines a first cross-section of the article; raising or loweringthe first solidified layer to provide a second fluid layer of the ink ata surface of the fluid ink in the container; and selectively applyingenergy to the ink in the container to solidify at least a portion of thesecond fluid layer of the ink, thereby forming a second solidified layerthat defines a second cross-section of the article, the firstcross-section and the second cross-section being bonded to one anotherin a z-direction, wherein the ink comprises the ink of claim
 1. 18. Themethod of claim 17, wherein selectively applying energy to the ink inthe container comprises partially curing the ink.
 19. The method ofclaim 18 wherein partially curing the ink primarily comprises(meth)acrylate polymerization.
 20. The method of claim 19 furthercomprising post-curing the three-dimensional article following formationof the three-dimensional article, wherein post-curing the ink primarilycomprises cyclopolymerizing the cyclopolymerizable monomer.